Kitchen Refurb - Any recommendations

We're thinking of doing some work to the kitchen in our Gardens house. Basically knocking the whole shebang down and re-building from scratch with a new door through the back wall (the kitchen currently opens into the side return). As well as the new door, I expect it will involve new wiring, plumbing etc.

We're new to this kind of work. Does anybody have any recommendations or advice for where to start?