Your ability of receive all the Freeview transmissions depends on the suitability of aerial
the design style,
the "group", and
its physical location.
Standard type - Yagi aerial
The standard type of TV aerial is known as the Yagi aerial. It is mounted on a pole, and consists of a rod with a reflector (shown green) at the back and many spiky elements (in grey) at the front. The connecting cable connects to the element nearest the reflector, known as the driver (shown in blue).
These Yagi aerials are directional and so pick up signals best from a transmitter that the rod points towards. The more elements the aerial has, the better it picks up a signal and becomes more directional.
A standard-type aerial is all that is required for digital TV reception in most places. These antennae have between 10 and 18 elements and a single reflector. These are recommended for new installations for good digital television reception, but will more often than not function perfectly in good reception areas.
Typically these aerials are designed to receive only some transmission frequencies - see "groups" below.
High Gain aerials
These aerials are designed for poor digital reception areas, and have two reflectors. For maximum signal strength, some digital high gain aerials have up to 100 elements. Since the switchover to digital-only transmissions back in October 2012, most UK households now have good quality digital TV signals.
A more expensive aerial is only required where the signal strength is low, but can often provide the whole Freeview reception where it might otherwise be impossible.
The CAI (that represents aerial installers) has four standards for digital TV aerials. The highest standard "1" is for homes on the fringes of coverage areas, intermediate standard "2" is suitable for use within the coverage area; minimum standard "3" is for good coverage conditions.
These aerials can be either wideband, or receive only selected frequencies - see "groups" below.
You may haved used a 'Grid aerial' for analogue reception, but as they are generally unsuitable for Freeview reception, they have now generally been replaced by the Yagi type. However in some places a Grid aerial installation may work for Freeview: otherwise replace with a standard Yagi aerial.
Indoor aerials are generally not suitable for Freeview reception. In areas of good signal strength it is often possible to receive some transmissions. Even where an aerial works, people often find that may get interruptions to their viewing (or recording).
Loft mounted arrivals are not generally recommended for Freeview reception, as the roof tiles and plumbing will degrade the signal. Some compensation for this loss of signal can be made by using satellite-grade cable to connect the set top box to the aerial.
The best position for a TV aerial is mounted outdoors, as high from the ground as possible, pointing directly at the transmitter. The signal can be blocked by hills and tall buildings. It should be positioned away from any other aerials.
Horizontal or vertical?
The transmitter will either use vertical mode which requires the elements of your aerial to be up-down, or horizontal mode which requires them to be level with the ground.
Both analogue and digital television is transmitted the same group of transmission frequencies (known as channel 21 through to 60). A coloured marking on the aerial shows the group.
To create the best possible analogue picture, TV transmissions from adjacent transmitters have been designated to several different groups of frequencies. By using an aerial that receives only the channels in the correct group, the analogue picture can be kept free from interference.
To receive Freeview transmissions from the same transmitter it has been sometimes necessary to use frequencies that are not part of the transmitter's normal group. When this has occurred, the aerial will need to be replaced with a "wideband" aerial (also known as group W) - one that covers every group.
As Ofcom is planning to move the TV frequencies again - perhaps as soon as 2018 - it may be wise to use a wideband aerial if you can to ensure you can keep viewing Freeview for many years to come.
Your Australian TV may not be suitable for UK terrestrialdigitalreception. If the information available on the digital transmission systems used in Australia is reliable, then they use 7 MHz channel separation but in the UK we use 8 MHz separation. That means the multiplexes are transmitted on different frequencies here compared to Australia. Some TVs have a setup facility to change it to recognise 8 MHz spacing, but many do not. Further, there are some differences in the encoding methods and hence your TV may not be able to decode all the digital signals.
I agree with MikeB's suggestion that you obtain a UK digital set-top receiver. Some are quite cheap (but may suffer from reliability issues) and you can get a Freeview PVR so you can record as well as watch. I'm sure MikeB has some ideas on what make/model you might buy.
Communal aerial systems (ariel is a typeface style) can be useful as long as they are well maintained. You might get to know neighbours and discuss their experience with the aerial system, but remember that some may be using satelliteservices via a dish which is completely different.
Signal reception from Black Hill is your location between Paisley and Govan should be quite good. The signals are available on UK channels 46, 43, 40, 41+, 44, 47, 32, 35 and 51 (local services only). You can find more details by clicking on the 'digitaltrade.uk' box (links to Coverage Checker - Detailed View just at the bottom of your posting.
We are indebted to Mike P for an illustration of Muphry's Law.
"Arial" with penultimate A is a typeface
"Ariel" with an E is many things; notably a nymph/spirit in Mr Shakespeare's "The Tempest"
When I brought a Toshiba TV back from Singapore I knew it needed adjusting for sound separation (+/- Hz from the picture carrier) I phoned Toshiba UK who said they could do it, for a very low fee, at one place only in the UK, but that I would have to arrange shipment to/from Clapham, South London. About 2 miles from my home in Herne Hill
I got so carried away with my story that I forgot to say that you should look for your TV's make model number etc then either google yourself for spec. and manual, or post here if not clear on such matters.
Wiki has various info about naming terms but depends how old yours is
Arial and Ariel are both type faces, originally depending on the supplier of the lead setts used for manual typesetting. European suppliers (including UK) tend to use Ariel in my years of experience (back to the fifties!) and Arial was originally used in the USA, but that has now come into use in Europe as well. So both are correct. But neither, as we both say, are anything to do with devices used to receive RF transmissions.