I have one spare way on a MEM Memera 3 CU fitted with cartridge fuses (circa 1990) that I want to use to feed an MCB/RCD shower unit. My local electrical wholesaler sold me a 40A MCB (Eaton ALB401) but it doesn't fit. What I need is either a 40A fuse carrier and fuse or a 40A plug-in MCB. The blades on a Wylex plug-in MCB are the wrong orientation (90 degrees out) and are the wrong spacing anyway. Can anyone help please?