Attention Sparkies! Help needed - power to outbuildings

[GreatOldOne]

Hi chaps,

I'm building a shed in the back garden to house my Lathe and other machine tools I plan on getting later on. Obviously this will all need power.

I need some advice on the best way to run the cabling to the shed.

Here's a rough, not to scale layout of the house and the sheds:



The main consumer unit is in the garage.

My initial thought is it would be easier and cheaper to take a feed from the consumer unit out of the garage wall and then straight up to the loft, with the cable in some galvanized conduit. Then run the cable through the loft to the opposite wall and then down toward the sheds in more conduit, with the main feed ending up in the workshop and a separate small consumer unit there.

Here it would feed 4-5 double 13amp sockets and some fluorescent lighting, and some form of light in the shed down the side of the house.

What I need to know is would this be OK by the electrical regs?

I know this sort of thing is notifiable to the powers that be, so it would have to be signed off by a qualified professional - but how much of it can I do my self, and what needs to be left to the Sparkie?

I've tried researching this myself, but get lost with earthing methods, cable cross section, separate earths, Part P and voltage drops.

Other things - the Lathe is 1000w, 13amp. Any other machine tools would be of similar rating, but unlikely that they would be run at the same time. An outside socket on the wall of the workshop would be nice for the lawn mower.

Thanks In Advance,

Jason