I think the overall picture is that Luton can struggle to cope with business jet traffic with regards to parking and is way out in front of any other London airport in part due to it being available 24/7.
Stansted, which is also 24/7 should be doing better.
Both Farnborough and Biggin Hill are doing very well but have limited hours.
Northolt seems to have extra restrictions but again is doing well.
London City is too expensive and for some reason Southend is not even on the starting blocks.
I have read that putting an bizjet through Luton costs half the amount of Farnborough.
https://www.privatefly.com/private-j...ort-A8220.html
A few years out of date but worth a read for the stats
https://corporatejetinvestor.com/art...n-airport-601/