Window hard against wall

[Baz]

Hi all

I've had a look through forums but can't find the answer to a little problem I'm having
I'm doing a remodel and the client wants a window hard against an adjoining concrete block wall.
The closet I can get is about 250mm (about 8 inches or so)
Anybody have any suggestions?
I've tried everything I can think of in preferences but am now at a loss what to do.

Thanks for any help which may be forthcoming

Cheers
Baz