Hi Karen. The blast covers most engineers use are approx 3-4 inches square, which the Installer should have used to hide/repair the damage, this would be the cheapest fix for the problem, you could get a builder to replace the 2 bricks and have the holes re drilled but this could prove costly.
The only reason i can think that the engineer refused to drill near the window would be to avoid damaging the window and avoiding an insurance claim.
If you do pursue the matter the engineer will have public liability insurance to cover such unfortunate circumstances.
Hope this helps