Cheers Ants didn't realise you had same problems until Jboy text me last night! thanks guys for the other suggestions think I will try 2ozs cloth and resin first and see if it helps.
Shame SM choose to use ABS rather than a F/G molded tub given that on the A4 it needs to be constantly removed/replaced for battery access etc.
Its good to see Ziv has started an assembly thread on the A4 as there's not a lot on RCU about the SM version and would have thought it was a popular choice for a lot of "scooter" enthusiasts as it's one hellava nice aircraft in 1/5th scale!
Cheers
Rene