Without knowing the address or postcode I was told "No" by the receptionist. When I asked if she was sure she explained that "I didn't know what I was on about and asked if the fitter was a planning officer?" At this point I gave up and just said "okay". I mentioned this to the fitter who was insisted I took it further so I faxed the council with my query. Two weeks later, no response. When my fitter came back from holiday he chased it up.
Six weeks later and 4 weeks after my fax a planning application pack has arrived and a letter explaining that permitted development rights have been revoked and I need apply for permission.
I now understand why some people are tempted to ignore planning applications for things like this!