Adding internal fuses to Ferranti 255 - A Good idea?

[Yorkie]

As an aside, I've often wondered why most continental radios of that era are internally fused, and British sets seldom, if ever were.

Because unlike UK 13A plugs, continental mains plugs don't have fuses in them. That said, as we know, UK plugs come with a 13A fuse as standard, which is often not changed for the correct lower value of fuse called for by the appliance. (1A fuses for 13A plug-tops aren't so easy to find). If the radio has the facility to add a couple of fuseholders, why not? The added protection can only be for the better.