Anyone got an "idiots guide" to changing these?

Its one of the items on my winter "to do" list.

I'm planning on doing the front and rears, I'm sure its not too difficult but any little gems of wisdom would be appreciated

Ta

Undo the old ones, fit new ones in place, bleed the system with fresh fluid. Make sure you use new crush washers.

Easy.

Are you buying a kit (like Goodridge or HEL do), or lines and fittings individually?
A kit should come with everything you need, and be the right lengths.

Cover all the paintwork in the immediate area with cloths; brake fluid can ruin a paint finish. If you can't, keep a couple of pints of water handy, to quickly wash off any spills.

And use the right sized spanners and allen keys, so you don't damage the new fittings.

Apart from that, it's a pretty easy job. Even I can do it. :)

Take photos of line routes and changed one line at a time.Wezmoto did a good deal for goodridge lines on ebay.

Also worth remembering to bleed the master cylinder too. It's quite common to get air in it and it can be a sod to get out.