I flew the Ascot to BUR SVFR route today for the first time, heading up from MID to Denham.
As several people said above, it is very straightforward; much more so than threading one's way up past Farnborough, Blackbushe, White Waltham, Booker etc.
It was a bit of a change of scenery, a nice view of the Heathrow runways and Windsor Castle and the quietest frequency (125.62 at the moment) in west London!
Must try it more often.