Seem to be posting a lot at the moment - it won't last!
So, many years ago I had a load of 1/300th scale WW2 stuff - still, actually. Some of them were the kind that had metal wire as guns - can't remember who m,ade them now.
Also had loads of terrain, quite a bit of it being from Irregular Miniatures in fact. Anyway, some of this I put on various bits of scrap plywood and added things like walls made from matchsticks. I've sorted out some of that old terrain and put it together with the new MDF buildings - some restoration may be needed but overalkl I've got enough to act a functioning terrain board.