Hi, if getting back to the CU is not an option, instead of spurring off a socket via a Sfs putting the rating down to 13a. Could you spur off the socket and take it down to 20a or 16a instead via a submain to allow for that extra kW if needed. If the cable size was sufficient for the length. For a garage sub main wired in swa. (32a ring circuit). In theory if you had sockets on a 16a rcbo and lights on a 6a then it's under the 27A limit generally a 2.5 can take. Thanks