Thanks for your replies Collectors and Sparx. So when you say "link both L & swL together at fan", I presume you simply mean put both wires into the same hole in the junction box connecting to the existing live wire coming out of the wall?
To whoever has put aside their turkey and Christmas pudding left overs and is surfing the net... I've scored everywhere to find the answer to my problem but can't seem to find anything that suits... I have recently had my bathroom refitted (but electrician has now moved onto other jobs) and it is co...