The 4 large centre studs were always there, I'm hoping it won't be an issue. The new barrels are slightly higher than standard but Mr Map assured me I would have no problem . The way my luck is going I won't hold my breath
I'm a little loathe to start messing with the pistons too much .
Checked emails while I was typing this , Mr Map says don't cut the pistons & email him a set of numbers embossed on the inside of the pistons to find out what happened . He will then send new rings & clips.
Guess he is working on a Sunday