This is way down on the list, I'm a Euro and a Brit, but that is way way down on the list, it saw very limited service.
Catalina is the obvious RAF aircraft that is missing, that US players can enjoy too.
Swordfish. Beaufighter.
There is a strong case for Beaufighter, it was multi-role, nightfighter and anti-shipping.
I'd even like to see Wellington and Halifax, they fought for years and years, the Defiant was very brief.