if I were buying I'd avoid Brentford. I lived in Kingston & still keep property there, in the next few years with rising interest rates non prime areas will at best stabilise, at worst bust.
I'd stick to established areas with good transport links - Kingston, Richmond, Surbiton etc.
I agree entirely with all of this and could happily bang on about the merits of these areas but I have no idea what the commute (by car) to Uxbridge would be like? As others have said don't underestimate what a mind numbing, soul destroying experience commuting by car in and around London can be!
The other things to maybe consider are:
How often do you want to get into central London? Every week, the odd night out?
What do you want out of where you live? (Good night life, easy access to green space, decent cycling, pubs, family life vs single life etc?)
Whatever the answer to any of the above is, I still wouldn't live in Brentford!