Chri5,
Currently (from memory, as I'm not at home) the fuseboard looks like a bit of wood mounted on the wall inside a cupboard. It's got one big black cable coming in from outside, the casing of which stops at the board and exposes the two smaller black cables. Im told these shouldn't be exposed like they are.
There are circuit breakers for four circuits, and one main switch to turn off all four. There are generally two wires, red and black. There is a black box, maybe 10cm square.
The meter is next to the fuseboard. In the cupboard is also a white box/socket with a fuse casing that pops out, the fuse is out permanently as pushing it in causes the ancient burglar alarm to go off...
I wasn't aware that they had to let my electrician in to a supply room, thanks for that. The caretaker claims not to know where it is, he might change his mind if I tell him my fusebox is getting hot and smoky and smells funny (it's not!). Then again maybe not, he wouldn't switch off the water when my sink sprung a leak and my stop valve wouldn't turn. The poor plumber got very wet!
Also fitting an isolater for my flat is a great idea, as I think they have to switch off the power to the whole floor, so a one-off would be far better.
Thanks guys, all very helpful. Much easier for me to talk to the managing agents now that I've got an idea of what is needed.