Brian.
I don't live in Doncaster, but know various people who do. I would suggest that a good start would be to get to folk events in the area. A useful source of info is the Yorkshire Folk Arts web site ( List of folk clubs). I am also aware thet something happens on a Monday at the Ukrainian club DN2 4AD . This may be a mainly tunes session, but I do know singers who go there.
A good way to build up confidence is to find a crowd who are friendly and encouraging. The Barnsley folk club are a good bunch for that.
One mistake new timid singers make is to learn the most long and difficult songs they can find (or that is how is seems to a listener), with no chorus or joining in bits. All this does is expose any weaknesses they may have, including the fact that the more words, the greater chance of forgetting one. I am a great believer in keeping it short with plenty of chorus - mind you they said I had a good voice for silent movies...
Best of luck finding what you need.

By the way - isn't a singing coach what you get on a char-a-banc bus trip coming back from Blackpool?

Quack!
GtD.