How Much Would A White Filling Be If Done Private, Also Where In London Can I Get It Done Cheaply?

It’s difficult to say exactly how much a White Filling would cost as each Dentist’s Private fee’s will vary!
The surgery that I Used to work in charged from £70-150 depending on the location of the filling and the size!
I’d say your roughly looking at paying anything from £70 upwards and I don’t know anywhere that you would get it done on the cheap as white fillings are classed as cosmetic so where ever you go you’ll be paying private fee’s anyway.
You could try ringing round some private surgeries and asking them for a quote, some will be more than happy to help you out and others will not give out any prices over the telephone as their more than aware that you could end up finding somewhere cheaper!