Hi Nick,Sometimes the damned things blow for no apparent reason. Mine went in Matilda 15 or more years ago, but the replacement has given no trouble. Someone, a year or so ago (Jose?) mentioned treating the mating surfaces in a way that roughens them, to provide extra grip for the gasket. I don't recall the details, or the procedure, but it made sense. Anyone remember what I'm referring to?
If you have the head surfaced with a rougher finish, the gasket has a better surface to get hold of, so less probability of a blown gasket. It is even better, if you had the surface of the engine block done with the same surface too.
Jose