FYI Lee, I had a fault on my line which BT said was my problem, i.e. within my property.
I had the BT engineer rewire the line then debated with BT in regards to the £105 they wanted to charge me or whatever figure it was.
In actual fact it is the second time I have contested a charge levied by BT and the second time I have had the fee waived, so in the worst case scenario always remember to contest the charge.