You can use your own kitchen to produce food but you must register as a food business with your local authority. You will also need to have some sort of food safety management system in place, don't worry although it sounds scary you can use Safer Food Better Business which is a free pack from the food standards agency which you can read through and then fill in the gaps so it is relevant for your business, then you just need to fill in the diary every day and do a few extra checks depending on the food you are serving. Just go onto the FSA website and download it. I'd post the link but because I am a new user it won't let me
You should also hold a level 2 food hygiene certificate if you have already done one check the date as you should re do them every 2 years.
Hope this is helpful if you would like any more advise just give us a shout. I have been running food businesses for a few years and I have quite a good knowledge of current legislation.