So I ate them. And bought another box.
Took it to the party, left it on the cake table, came back after some lovely barbecue food to get a slice and ...it had all gone! Had to resort to licking up the crumbs left on the plate.
But all is not lost.
I've been invited to a 'Last Day of the 40s' party next weekend and it was suggested I could make another Malteser cheesecake for that. And this time the host has promised that we can sit in a corner together and share it.
The party house was on the North Gower coast and when I left the tide was in and the water lapping through the reeds, and the sun was setting rather beautifully.