but the artist doesn't have your local knowledge and contacts. The responsibility for promoting surely lies with promoters and artists. If the promoter is going to say "not my job, mate" they can't moan when nobody turns up.

That's what I would have said.

You make a a number of contacts with local radio and newspapers. Past experience leads me to believe that most local newspapers and especially free sheets will give you loads of copy. The artist will send you material so you don't need a secretary. But the artist does not have the local contacts you have. And if they don't do it automatically, tell them you want it. Many of them will send you posters in advance - all you need is to put the name of your pub/room on and stick them up - or give them someone else to put up in return for free admission.

After the first week or two the thing will run itself.