Thanks for the all the advice.
I'll definitely get an electrician to do the wiring.
Knowing that we can just run the SWA along that wall will make things a lot eaiser.
We are looking at the option of a pond in the garden with associated pump and maybe some lighting, but we have a hurdle to overcome before we do too much planning:-
How do we route power from A to B without digging up the patio?
There is a cable that runs from the consumer unit and...