For an apartment block where all meters are housed in one room with steel galv trunking running from the fuseboard (Beco/Ryefield etc), what kind of cable is used between the fuseboard and the meters?
Depends a bit on the age and size of the installation. Nowadays, with insistence that it be TNS and meet BS7671, and be tamper evident, the cable of choice for any long run may be SWA, or just maybe split concentric. In older set-ups that were once the electricity board's equipment but have not been DNO adopted, maybe earthed concentric as well, or if older still maybe singles - even cloth served rubber covered singles still in service in some just post war but not many of them left.
If the run is very short, say on one wall in a locked cupboard or boxroom, then it may be something more like an array of meter tail style wiring.
Also the means of isolation may vary by DNO - the more recent docs by UKPN and others now request all-pole isolation at the Ryefield end of things, which would once have been a no-no, the thinking being that not being able to turn it off may discourage abstraction. The opinion seems to be moving towards, it is better to make it physically secure, or at least temper evident in other ways, and provide a means to turn it off for major works or in case of trouble.
If instead the meters were near each flat, you may see a thing that looks like a company fuse next to each meter to allow local isolation, but with a 'red link' or removable shorting block fitted in place of the fuse - the real fuse of course is in the Ryefield box, near the incoming cable.
