The small white unit (just above the rubber boots!) is the Hager 'consumer unit' feeding the dedicated ring for my audio system. Within the unit is the main 100A residual current circuit breaker (RCBO) and a 32A MCB (miniature circuit breaker).
The large white unit above the Company Fuse, where the mains cable comes into the house, is a Wylex 8-way consumer unit covering the rest of the house. It too has a 100A RCBO mains circuit breaker, with the other ways populated with RCBO's of the appropriate rating: 5A for lighting, 32A for the general ring main and sockets, and 32A for the cooker.
The two consumer units have their incoming 'tails' joined using a Henley block (the unit just behind the rubber boots, with the Danger label affixed), and thence to the electricity meter; to the left and out of the photo.
If you have a spare way in your consumer unit then you can fit a RCBO unit to cover your dedicated socket or ring for your audio system. If you only want to have the one socket, then the rating of the RCBO will need to be 16A. I had all the work done by a professional electrician so I could have the necessary paper work for insurance purposes.
Trust this is of some help.