A foot note from my experience..
Just had most of the upstairs and loft conversion plastered. The plasterers came, went, came back again, went, came back again etc. and left a complete mess every time... carpets, bannisters, beds.. all splattered. Whoever you get make sure you protect everything because chances are they won't even if they say they will. And try and get it done in one day, if possible.
Friendly blokes and they did the job but they didn't give a fook.