Suggestions for moth id?

[jeremiah]

This is a very long shot, and I have no pictures.

Some years ago, in its youth, my cat brought in large moths that it caught under next door's security lights.
I never saw the whole moths, just the wings sticking out of Sidney's mouth.

The wings were large, (3-4cm) not hairy at all, veiny, hard looking, slightly shiny slate grey in colour, no spots or other markings.

The best way to describe it is the veiny look of a burnet or cinnabar moth, but completely plain.

I've looked at some pictures on the UK moths site, and think maybe they were red-necked footmen, but would these turn up in South London?

[Jenny W]

Size wise they sound like Hawk-moths. It sounds to me like they have lost all their scales, which would explain why there were no markings on them. If you can remember the general shape of the wings (if they were intact that is!), then you may be able to narrow it down.