Plum sawfly or moth ?

Once again our small crop of plums don't look nice when cut open due to "a brown mess" (could be frass) around the stone.

I sprayed the tree when required to to aleveate brown rot, but I think the brown rot is secondary to this other problem, entering the fruit through insect damage.   

Any recomandations as to how to deal with these flying pests, if indeed it is them wots doing the damage?      Cheers,    Tony.

I've indentified the little begger,  Plum moth, pink with a grey head.  Normally I'm a sort of live and let live sort of bloke until they come between me and my plum jam or plum wine.

Our Victoria plum gives a load of fruit one year and not so many the next, so next year will be a bumper year and I'll be ready for the little divvils !    Cheers,   Tony.