I would like to stop all incoming international calls can anyone explain how I can achieve this with BT. Neither I nor my wife have any international connections so do not want to phone other countries or receive international calls.
You can only do that with either one of the new phones from BT, see
BT Launch new phone to block unwanted calls
Or with an external device like TrueCall.
I suggest your purchase the BT6500 cordless phone, can block international, witheld, payphone plus any 10 numbers of your choosing.