I wanted to bring this to people's attention as I believe it was missed in my original post, then voted cold as no one could confirm if it was true. I now have confirmation it works.
So, to have Hive installed by British Gas it is £250, they are now offering a £9 a month offer where you pay £9 for 24 months totalling £216, you could do this to get it cheaper but you can get it for even cheaper...
There is a flaw in the T&C's where if you have it installed then cancel 15 days AFTER its been installed (not before) you pay £150 to get out of the contract. You do not cancel before the 14 days otherwise you lose the remote control element of Hive (not being able to control on phone). Once you pay the £150 fee to exit the 24 month contract that's it, all done. You have Hive for £150 supplied, installed and setup.
I did this back in February, I originally thought I would have to pay at least one months subscription of £9 but did not :)
All you have to do is call 0800 691 1406, organise a install date then 15 days after installation, call British Gas and cancel the contract
Note totake advantage of this you have to be an existing British Gas customer (energy, HomeCare or a 5 year warranty)
My original post - http://www.hotukdeals.com/misc/hive-9-a-month-150-cancellation-fee-making-159-installed-2601223?p=30528586#post30528860
 Available to new and existing HomeCare customers only. If you cancel your HomeCare product and have no other products with British Gas, the price you pay for your Hive Active Heating will increase to £10 per month. If you purchase an eligible British Gas product again in the future, your price will go back down. Prices subject to change.
 The subscription is ongoing and will continue until cancelled. Cancellation fees apply in the first 24 months. A fee of £150 will be charged if cancelled within the first 12 months and £70 if cancelled after 12 months but before 24 months.
FULL T&C's here - https://www.britishgas.co.uk/aem6/content/dam/britishgas/downloads/Hive/Hive-active-heating-subscription-terms-and-conditions.pdf