This is the first time I have replace the group head seal on my single group San Marino.
Getting the old one out took a while as it was well and truly cooked. Found in the end "Bolt off" and screwing self tappers into it worked.

Problem now is the new seal won't go in. I watched the you tube on replacing it using the porta filter to kind of force it in but it just won't work for me.
I checked the size out all OK. I've tried lubricating it, putting it in hot water

It seems there is just too much gasket to fit in the groove.

So what am I doing wrong, it can't be this hard surely

Any advice much appreciated.