Talybont Rooms and bed sizes?!Watch
To the best of my knowledge, all the beds in Cardiff Uni accommodation are either singles or small singles (which are 15cm narrower than a single). I was in University Halls for my first year on a small single with a springy mattress that was horrible to sleep on, so I invested in a padded mattress protector. The Talybont residences are a bit more modern than Uni Halls and I've heard the mattresses are nicer.
There are really useful videos on Youtube from students showing their accommodation. Here are two showing Talybont Court and North:
Hope this helps,