Well I do have six ring mains in this house....

Kitchen and utility
Lounge and master bedroom
Dining room and bedroom above it
3rd reception room and dormer bedroom and office
Loft sockets
Outside sockets.

I don't think there is a limit on the number of sockets on a ring main, but I think there is a maximum area limit of 100m2.

In any case, you do have to think about the prospective loads on the ring main which is why there is a ring main dedicated to the kitchen and utility room.

The outside sockets are on their own RCBO so that if anything happens outside, it does not affect anything in the house.

The loft ring main is on account of the computer equipment and TV/radio headend & multiswitches.