In reply to Zygoticgema: I think some mortgages (and properties, for that matter) have restictions and running businesses from home, but that's to stop people starting glue factories or brothels and such like so I wouldn't worry about it (unless you are starting a brothel, of course.)
If you use part of your property to run your business you can claim reasonable expenses but don't overdo it by charging yourself 'rent', otherwise the revenue will deem part of your house a business assest and charge capital gains on a proprtion when you sell.
Above all there's one thing to remember - they're not out to get you. As long as you are not trying to fiddle the system, and are prepared to keep sensible records, then you can ask C & R questions and they will give you sensible answers, they aren't looking to catch you out.