I think the shirt ironing service is a great idea. I am not sure what the going rate is up in town, I think it used to be about £1 quite a few years back when I worked in central London (didn't use it personally but quite a few of my colleagues did) so I guess it would probably be about £1.50 now. Surely if a Forest Hill laundrette could undercut this it would be popular with office workers.

Another service that could be popular is simple clothes repairs and alterations - how many people have sewing machines at home and are able to take up trousers / repair clothes / replace zips? Particularly on something like a suit or a coat which would cost a lot of money to replace. In cash-strapped times people are surely more likely to pay a few pounds to repair something than replace it altogether. I know that personally I try and repair my clothes as much as possible..

There are lots of ways a laundrette could be made financially viable, but at the end of the day it relies on someone to take on the business, which is what seems to be lacking here...