Can anyone recommend a person or firm who will fit a wood-burning stove? It won't be a straightforward job as I don't have a chimney (at least, I may have one behind all the plasterboard, but I don't know) and then there's all the plasterboard...! So I'll need someone who knows what he's doing. Any recommendations would be useful, thanks.

A good start point for reference is stovesellers.com.
They are an English company based in the Limousin, but provide a wide range of information regarding appliance selection etc. and are very helpful on the phone and mail.
Also try the sites of Phillipe Design and Franco Belges for local stockists of appliances.
Both local agencies came to us and provided a very comprehensive outline of romm size to model heat output and chimney requirements and also the legal issues new in 2009 for installation.

Thanks for the info. I've looked at all three sites briefly and they seem very informative. When you say " both local agencies," which two are you referring to? And who, if any, did you decide to use?