I have always been insured with the NFU (i'm 20 now) and they have always been reasonable. Started on a series then a defender and having had an accident, had no problems with them paying up.
They are starting to get a bit ****y now as i want to fit a rollcage but are fine with the 300tdi conversion, 2 inch lift, larger tyres, soft top, disco axles etc.
Adrian Flux seem very helpful and understand modified land rovers a lot better than the NFU but due to my age refused to give me 3rd party cover on any vehicle, wheres for £100 more I can get it with NFU which is very helpful. When i got a quote from Adrian Flux, they offered me discounts for being a member of LZ and also for being involved with the Uni off road club
It is illegal to be the main driver and insured as a named driver. Jak1471 is correct, adding your parents as named drivers knocks the price down nicely.
Harry