I firmed bath for aerospace ahead of imperial. Mainly because I liked the place more than Imperial. My friends were like WTF, but honselty i couldnt give a damn. Do what you think is right, maybe try visit the two places. Imperial has a better rep, but rep only gets you so far. It might get you a better starting job, but its what you do when your employed that really matters. I imagine F1 teams will be more interested in your final year porject than the uni you went to too. Theres no point trying to get a job in maclaren if your project is not in any way related to F1 and shows that you can think outside the box. Also, the amount of people employed by F1 is so small that going to Imperial, rather than bath only increases your already low chances by a tiny amount.
Its really down to whichever place you like more. Theres no point spending 4 years somewhere you dont enjoy. Visit both places (if you already havent) and pick whichever you like more.