Ok, I've made the sides and front (from the blurred Imperial War Museum pic in the Bellona profile) of the wading gear, but don't have any info on these problems.....
1) The extended sides just seem to butt onto the top of the existing side, with the joint reinforced at the corners. The extension would have been steel plate, but how would the joint between that and the existing side be sealed - the standard was 'admiralty cloth' a thick cloth coated with rubber glue, or tape of the same stuff; or could it have been a rubber seal as used on LCT doors?
2) how would the large gaps around the spade have been sealed - either inner steel doors or tarpaulin + rubberising would be my guesses -
anybody else got any thoughts on this?