This has propably been answered somewhere but my fuse box has 1x wylex 40 amp mcb for shower and 2x30amp 2x15amp and 1x 5amp fuse holders that you pull out and has 2 vertical "pins at the rear to push into the box.I would like to replace these with mcb,s but the ones i have seen in local shops have horizontal pins if i buy wylex mcb,s are they a straight fit because i see they have some kind of carrier at the back or is it a wiring job.