House phone works OK no noise on the line,
My reference to a "noisy line" was very much meant as noisy to all the frequencies that DSL is using, rather than noisy in the audible frequency range.
What your modem hears when it tries to sync is the equivalent of sitting in a pub, with 20 other conversations going on around you.
put the HH5 back inline but it must be faulty as It will not connect to internet,
I wonder if this is a problem because your HG612 has allowed G.INP to activate on the line, and the HH5 cannot cope with that.
so have replaced with the V130 better rate than HG612 but still not in the BT range for my line.
I'd be tempted to leave the HG612 in place ... at least while you are reporting the fault to BT, and Openreach are investigating.
The slower speed might make them slightly more likely to deal with the issue.
I believe a pair swap would be worth trying but how do I get BT to agree?
You probably can't ask your ISP to order Openreach to do a pair swap. All you can realistically do, for now, is to report the slow speed and ask for an engineer.
When the engineer turns up, he'll have to go through his tests first, and may make some other suggestions. I guess you have to play it by ear to figure out if he is fobbing you off.
Note that the ISP may need you to go through some rigmarole before they'll book an engineer. Probably including use of the test socket, an alternative filter and an alternative router.
What would be the cost?
There shouldn't be a cost for a fault fix. But I don't think there's a way to order a pair-swap even if you were willing to pay.
I have a hearing problems and find it difficult using the phone and online chat all I get is the Indian support team (not helpful at all)
I believe you can ask the Indians to put you through to someone in the UK. I also thought a lot of the support work had been brought back to the UK.