The long and the short of it is after another hour on the phone to TT where I did actually talk with a technical UK
support manager is
For TT 76Mbps Fibre + Boost Incl. Line Rental the threshold that TT would consider they were defaulting on the contract was 25Mbps [one third of their Max]
They agreed that they indeed passed on the call setup charge and charged for 0845 & 0871.
I complemented them on their 24 months FIXED
price offer and also their claim to offer new deals ongoing to existing customers too
However, I declined to sign up to what was reasonable pricing not just for Fibre Broadband Boost but also their Anytime and International calling plans [despite having to passing on the call setup charges and the 0845/0871 calls.]
I may be a total pedant
as it seems nobody else had voiced such objections, BUT I couldn't agree to sign up to their 76Mbps +Boost when their minimum level of service was 25Mbps
before I was allowed to cancel the contract [note: this was based on the assessment of my line, YMMV].
I said I doubt their lawyers would refrain from enforcing the contract with gusto if the service dropped to 26-27 Mbps and I tried to terminate the contract. The guy said he couldn't argue with that posited scenario (however unlikely).
So, to finalise where I'm at and where I'm going, and I must add that without THINKBROADBAND.COM staff and contributors I would not have had such input,to help with my deliberations, however in the end I have ordered a solution from an internet and phone provider where the internet service is based on a service provided by Entanet and phone provision by bulk purchase directly with Openreach which in total is a bit more expensive than I had planned and which won't see me in the ranks of the 80/20 club due to the limitations of my line, but potentially better than what I have now with reasonable line rental and call charges.
Thanks all for your patience and I apologise for posting the entire webchat with TT but maybe those who cared to plough through it realised how pathetic the dialog was.