I'm not sure if mail will be queued, so it might be worth resending, just to make sure.
Personally I don't think stuff is held over, especially mid-run if it is by then considered last weeks news.
Some directors do tend to hold over some stuff, (as reserves, should sketch count be down one week) but mainly generic sketches.
For example, last week my Metal Detector sketch was used (a generic skit about a metal detector installed at a school entrance - a pupil goes through clean and is then tooled up by security) which I actually submitted weeks ago to the previous run.
A question. Does anyone know if or when we get paid for sketches used in the recent NR London Previews?