Graupner is the EU distribution partner for FT board, Model Shop Leeds are good for FT stock, but the FT board is out of stock everywhere in the EU right now, possibly due to the new white version being produced. MSL told
@CarolineTyler they had some on order.
The larger planes actually work better in heavy UK 5mm foam board, as air molecules don’t scale downward, just put a larger motor and prop on than the size listed in the plans, I keep the KV low on teh big stuff and run a 10x3.8 APC or slow fly type prop. Check motor thrust figures, UK builds are usually 40% heavier all up weight.
On short nose designs like the Scout or Speedster with big tails, add 50mm to the nose length in front of the wing when you cut the fuselage, this will give you more to play with on the CG.