Day 299/19. I don't think the museum has one .....

Last winter I made a couple of model aircraft for the Museum where, when I have time. I volunteer.
A damp, rainy miserable day today, so I made a beginning on the first for this winter. I'm pretty sure they don't have one of these on display as yet. But what is it?
Let's look at the clues..... 2 pilots with room between them, 3 gun turrets, a strange shaped canopy. And what is that in the background? Can any WWII experts work it out?