A single conductor to each service is the ideal situation, however to use a single conductor to one service and loop it on to the next service is totally acceptable.
There is a suggestion in GN8 that a looped service should be unbroken to avoid the chance of a disconnection at the first service also causing disconnection at the second service.
Though it is interesting to note that this will only be applicable if someone carefully undoes the wiring connections, in which case they would probably be careful to reconnect, rather than just snipping the conductor.
However where the conductors are not looped there is no suggestion that they need to be unbroken and in many cases will often be jointed several times before they arrive at the MET particularly in large installations.
There is a suggestion in GN8 that a looped service should be unbroken to avoid the chance of a disconnection at the first service also causing disconnection at the second service.
Though it is interesting to note that this will only be applicable if someone carefully undoes the wiring connections, in which case they would probably be careful to reconnect, rather than just snipping the conductor.
However where the conductors are not looped there is no suggestion that they need to be unbroken and in many cases will often be jointed several times before they arrive at the MET particularly in large installations.