Contact your local helicopter operator and have him sling your pool.
I have done that often. It´s often the easiest way and if you count all the cost of getting a truck (lorry) with crane and personnel for several hours versus a 10 min sling load for helicopter its easier to just pay for the helicopter to do the work.
Although I´m not that familiar with UK regs, the trouble for you people getting permits and such may be prohibitive for such a job in your area!?
In normal countries where helicopter´s are just seen as work equipment like any other tractor or lorry this kind of job is a no brainer. The pool probably doesn´t weigh more than about 300 - 500 kg so its a JetRanger job.
JetRanger costs about 700-800 UKP/hr so ask a local operator how much ferry time and how long he would figure on slinging that pool one km.
Best of luck.