Unfortunetly, with the larger Airports around London (Luton, Farnborough, Stansted etc..) all getting busier (more congested) with most/all requiring slots, handling etc.., you'll probably find more aircraft such as King Air's & Pc12's making use of the smaller GA Airfield's around the London Area. (I'm sure Luton would rather handle a Gulfstream than a Pc12)
North Weald has a couple of based King Air's (along with the occasional visit of a Challenger bizjet!), Denham see's regular visits by Pc12's, Blackbushe has regulars visits by King Air's, Beechjets, Citations etc & Fairoaks has a based Pc12, based TBM700 & a couple of King Air's along with regular visits by such aircraft. Also, Stapleford has a couple of King Air's based.
Wait till VLJ's really start to take off (excuse the pun) & start to frequent these smaller Airfields!
FC