Go to where you want to go and if that's Nottingham then so be it.
You can't let her guilt trip you into going to UCL because at the end of the day, if you end up going somewhere where you don't want to be in the first place, you're more likely going to end up hating it.
You shouldn't let your mum influence your decision, she has to realise that one day, you'll finally have to move out. It's most likely an empty threat, but even if she does move into Nottingham, you can easily try to avoid her, after all it is a massive place.
At the end of the day, it's your life. Not hers.