I have two wylex standard cu's ( 3 way and 4 way ) which are about 25 years old and I have purchased wylex plug in mcb's to replace the rewireable fuses.There is a gap of 5mm between the new mcb and its carrier which exposes the live mcb connector.The base of the mcb where it pushes into its new carrier lies flush with the front of the main cu and cannot be fitted deeper into the cu. This is obviously a safety hazard as tiny fingers with metal implements could physically touch these connectors.The mcb's protrude further out than the old rewireable fuses preventing the old fuse covers from being refitted.I have put the old fuses back in to prevent electric shock until I have a solution. Are there any experts out there who know if there is a deeper cover or some form of shroud to cover the 5mm gap.As a last resort I will return the mcb's and fit a new cu but plug ins seemed to be a good option at the time. safety is my main concern.