G-Spots
I think you might be a bit behind the curve - we go into OXF fairly routinely, a couple of times each month perhaps, and the 1552m by 30m runway was brand new in 2007 when they put in the ILS - 30m isn't narrow?! When it was 23m, that was narrow. They've got F900s, Globals and Gulfstreams going transatlantic out of there and virtually all Hawker models can go anywhere in Europe and beyond from there - not everyone needs to operate at max gross?
I think you'll find the airport's owners have bought a few Embraer products (a couple of Flairjet's Phenoms and one of LEA's Legacys?) but the Lineage for one has apparently been sold - it's not theirs anymore, still has the old reg though.
Not wishing to dismisss other options - Southend, Cranfield and Cambridge also have their merits as London access points, but opening hours, ease of access, ground services, FBO standards etc. may be all of significant relevance to the originator of the thread? Our boss lives north west of central London, so the M40 to OXF is easiest for us. We've been Biggin and Luton based in the past with different aircraft. Kensington to Biggin can take up to two hours in south London traffic, whilst OXF is a bit over an hour most of the time.