Thanks Simon and Rob, all good info. The weight doesn't worry me too much, no current plans to fly but an excess baggage charge is better than a bent gun in the scheme of things if I ever do. The im3220 is looking like the way forward, I like the idea of more depth of foam plus space for essential tools and assorted 'stuff'. The 3300 is still an option as it's almost exactly the width of the back seat of the car.
Doing a bit of a change of kit after this weekend so will get the tape measure out on Monday once it's all bolted together
ISP Airstream MK III No 15 which is a bit poorly at the moment and having a rest
AA Pro Sport + Ginb FT8 stock + Bushnell 4200 6-24x
EV2 MK1 + Leupold Comp 40x
Weihrauch HW100 KT laminate
SBFTC Competition Secretary