Sills - repair

Just back from a MOT pass, but it has come with an advisory for rust to both sills.

Two questions.

1. They seem to be rusting from the inside, is there a drain hole I should be checking on?

2. This is an old car, so not necessarily looking for concours appearance. Is there sill covers on the market which can be tack-welded on? ( I would be happy with black stone-chip paint finish - don't think that it would look too bad.)