i live in central london and had coilovers on for a over a year and running them pretty low - it is doable but I dont really drive too much around town I normally head out of London on the weekends
some roads i just cant go down though and this depends on the borough - in angel for instance the speed bumps are like mountains and it would not be possible for me to drive around - luckily in wandsworth where i am they are not too bad but I have come across a few roads where it is just painful as even crawling over them you still get the odd scrape.
they are adjustable so if i did have to drive more in town then I would probably raise them