Customers have no protection from an external body i went around in circles on Ofcom's website and found nothing and so contacted the relevant Ombudsman who thought he may be able to help but not until i had complained to talktalk in writing , received a reply and allowed them 8 weeks to remedy the problem
He did offer a talktalk email address to use but i don't have it now ?
The engineer that visited me explained "service providers won't send us because they automatically incur a £55 call out fee" which is after all a years wages for most of talktalk's staff
So Frank - if i knew back then what i know now i would have changed the phone master socket which is two wires and they sell sockets in Maplin , £5 just to be sure the fault is not in my house . (change it back if the fault is not fixed or you will get a bill from BT when they come)
Phone the Ombudsman for talktalk UK office email and send your complaint/request for an engineers visit there .
Regardless of what they say you cannot be charged for faults outside your home .
The engineer also explained that they will change even a good master socket inclusive of the £55 call out charge which is the service providers and not the homeowners responsibility , though i expect a bill for that bit from Plusnet (phone chat terms & conditions blah blah blah)