Chris, Dave mentioned the seals at the oil filter (and I take it he meant O rings on oil pipes from the engine block). These same pipes also have seals at the other end where they go into the block. Mine had perished causing quite a bad oil leak that wasn't visible to. the eye from any angle. The O rings are penny cheap but an absolute pig to replace😡😡😡. I seem to remember having to make up a special tool to undo the bolt on the bracket holding the pipe into the block.
Cheers
