Go to Oxford
.....cheaper
.....an hour and a bit to/from west end (no worse than some others here)
.....longer opening hours
.....outside very busy LTMA
.....very easy access, hassle-free, very fast turntimes
.....from touchdown to leaving airport entrance in 5 mins
.....from 22 mins in helicopter (on-site) to London Heliport as alternative
.....maintenance for almost all biz aicraft types on site
.....friendly ATC, of course.....
Not that we're biased of course!