Cheers, good pictures!. Your pistons all look very black?! Glad to know is nothing serious, looking more closely those marks do look machined.
I am not looking forward to cleaning mine up tomorrow, my head gasket was completely buggered and parts of it remain on the head and block. Looks like it will be a painstakingly slow process, as i dont want to get crap in the cylinders or waterways.
That thing on no.1 is def a small hole, looks like something has been in their! just hope it has long gone!
Phil