Inner wall lower than outer, cavity closer gap!

[miked1]

Hi all

I've fitted cavity closers around all of the openings in my extension, but on a couple of openings the inner wall is approx 1-2" lower than the outer which means the following when fitting the cavity closer (double flanged):

1. If fixed to the outer brickwork, there's a gap below the bottom of it and the inner wall. What's the best way to bring this "gap" level with the outer wall so that the window cill will fit up against the new window?

2. If fixed to the inner brickwork, I could cut off the flange leaning against the higher outer wall. I'm thinking this is the best method as it closes the cavity best, but then I'll still have a problem of the gap to fill for the window cill>>??!

Any suggestions very welcome

Thanks

 

[NS215]

cut a little slither of block to make up the difference on the inside skin of some mortar if its not too low