Swansea Brew Club might be able to help. I don't think they are doing all grain brewing, just extracts. When last I was there they seemed very flexible. You could make you own recipe, use one of their's from the recipe book or have them make something for you. You could participate as much or as little as you wanted. They even had a list of people who may be interested in splitting batches if you were trying something out but weren't sure you wanted a large batch.
Even if they can't provide exactly what you are looking for they are right across the street from the Cheese Boutique so a trip over there is never a wasted trip!