Thin trim?

[cdbe]

I need to sort out these windows:

The gaps are up to 15mm and behind the silicone mess is mainly void. I'm going to foam them in and finish with flat trim - problem is that the windows have been fitted too far forward - so the trim will finish flush or in some places past the brickwork. All I can think of is some 1mm thick pvc angle cut down might look better - any thoughts or suggestions appreciated.

 

[Tigercubrider]

Could you use some kind of architrave type trim but use something like a dremel to scribe the difference for a good fit?
it might take a while up a ladder with repeated trips up and down for adjustments?

 

[crank39]

Foam right in the the back of the gap and then fill with silicone but then slide the trim in the gap leaving flush or just below the brick face not as you suggest placing it flat on the window, just an option you maybe hadn't considered, it also reduces the gap you have to silicone