Yeah you can buy a new phone with Bluetooth (BT), but that will cost a lot and you have to make sure it is unlocked or on the O2 network.
Hint from an insider, tell her to try calling Vodaphone, Orange, etc from her mobile enquiring about new contracts and see if she gets a call from O2. If shes a valued customer, she might well get a call from retention, then she can demand a better phone. Or call customer service and tell them you are not happy with the phone and see what they can do. O2 customer support are generally quite open to keeping people by offering them phone upgrades.
Alternatively I think I have a W800i somewhere with I beleive all the bits, you can have for free if you come to the Wales run?