Dang, that poor bike. 
Yeah, you really have to hate it when they do that to the case. How bad was the cylinder?
JB weld may be an option

would that mean every time i replace the piston i would have to apply fresh weld

So its in the shop at the mo and we're trying to find a way to get it done without having to take every single bearing out of each case etc
all i wana do is ride !!! garrr
there's also the option if 2 base gaskets
but annoyingly I am a perfectionist and like everything to be 100% so stuff like this bugs me and is always in the back of my mind lol