Wiring:
Deciding on the location of the switches, sockets etc is probably the hardest part. I'm putting pretty much all of the switches inside the airlock. Settled on having two, 2-gang switched sockets to the right at about 20cm from the floor, these are to power the DAW (PC) which will be raised from the floor on a shelf. Fan isolator and speed control to the left at shoulder height. Light switch to the right of the internal door frame at shoulder height.
All that was needed now was to feed the cables and clip them to clip them in place. I attached a length of plywood to the bricks where I needed to run the ring cable down to make it easier to clip the cables to. Then running the other cables for the lighting and fan connections along the outer roof support then along one of the joists. I added additional noggings where the switches are to be located to attach socket/switch back boxes to.
Currently there is a single T&E cable running from the house through a conduit in the open air. This originally supplied everything into the outbuilding: sockets & lighting. Obviously I'll be removing this but I am going to make use of the conduit to feed a CAT5 cable through to connect the room up to the outside world. So before pulling the old 2.5mm cable through into the house I'll attach the CAT5 cable to the end. I'll have a double CAT5 near the DAW (PC) inside the 'airlock'. One will link to the outside world, the other will be fed under the floor to the desk - eg. for the laptop.