Simon: "The crankcase is almost certainly Model 25 or Model 21 though there is a very slim chance it could be one of the earliest ES2s (before they were called ES2s) which had a two piece timing cover like the M25s. The timing cover now on the engine is actually Model 18/16H or whatever - you can see it does not meet the lower cover over the drysump oil pump housing. The Best and Lloyd pump is feeding the inlet union of the dry sump pump - but perhaps there was no actual pump in there and it was internally set up so that it fed the big end etc via the usual dry sump quill...Who knows!!"
