Bt Charges
BT charges £130 call out including vat per visit, if you require a telephone extension they will charge you another £75 on top of that making the cost £205 see here http://www.bt.com/pricing/current/Misc_boo/1393_d0e1.htm BT to come your home to diagnose a fault or telephone problem will charge you £130 – if the problem is outside your home then the charge will not be made, but if the problem is found to be in your home expect to pay the £130.
The telephone engineers listed on this website charge you less than what BT charges.