True. I hadn't really thought about the possibility of an external meter cabinet. So, IF there is an external cabinet, and IF the DNO/supplier didn't object to a switch-fuse and Henley being installed on their board, then that would probably be a simple and tidy solution (albeit it would require having the cutout fuse pulled to install it). It would also then be, with no wriggle-room at all (not that I ever thought there was much!), a notifiable 'new circuit'.Switchfuse in the (presumably) external meter cabinet. Job done. No RCD, no internal SWA. Everyone's a winner
Kind Regards, John