Thanks, Michael, for your reply.
This SALICRU brand stabiliser unit has two fuses: one with a 1A fuse (never blown) and another with a 1,4A fuse (which is the one that blows). We only recently set up the enlarger, and the fuse has only blown on us twice so far: the first time, during an exposure, during a session of using the enlarger (this was the fuse that the stabiliser came with originally -- who knows how long it was in disuse/use). Then, after that, we bought a 1,6A fuse because the electronics store does not carry the 1,4A variety. As soon as we replaced it, and turned on the lamp to focus for the first time, it popped. We replaced that fuse and have used it sparingly since (for a few days now) and no further blowing. The fuse we are using (I think) is a normal blow --neither fast nor slow--. I don't know whether slow/fast blow is something you can see on the fuse itself, since I can look to see what the original was. Unfortunately, nowhere on the unit itself is there any indication of what fuse rating to use. Would there be some advantage in using one or the other in this case?
Maybe the thing to do would be to use it and see how long we go before another blow. If it occurs at long intervals maybe we can live with this, too. Fuses are cheap.