Just bought this myself.
Use code ZG426 for £25 off. Starts off at £89.00 plus £3.95 delivery. Voucher brings it down to £67.95 delivered.
Not much else to say really. Good phone great price. O2 don't lock their phones so this should work on any network except 3. Well worth combining with http://www.hotukdeals.com/item/478584/its-back-02-12-month-sim-contract-8
If you are not honoured for the code they will order you to pay the discount back.
Read the T&C!
So make sure you honoured for the code (i.e. they send it to you) and then order!
Otherwise KEEP OUT!