The EC complaints team will be the one that works on behalf of the main BT board. There will be an equivalent one that deals with high level complaints within the OR division. Surely the ones you are dealing with must be able to speak with their counterparts in OR and get them to cascade it down through the OR management chain.
That's exactly how it should be beingn dealt with.
Yes it "should", but saying that, it still might not help due to they have to contact "Openreach" and most of they time it ends with a fob off date that comes and goes, like mine has done for 4.5 years and I have had an "Executive Level Complaints; BT Consumer
" on the case for the last couple of years.
Strangely enough I have got more information out doing research and openreach than what the EC Team have, which might of helped.
I have emailed everyone I could find, my Local MP which has done loads to help, BT, Openreach, CEO of Openreach (Clive Selley) and there was a few others.
But if you email them too much they just ignore your emails, openreach are also known to just stop responding when you show proof that contradicts what they have said, they really hate that LOL.
And to the OP, yes its annoying to know that the FTTP Hardware that would be used is live, in our case out of several linked FibreDP Hardware only one home can order FTTP and is currently using it since Jan 2016, to be stuck on ~4 Mbps when 4 doors has 330 kind of sucks.
But now according to the last email from Openreach they say light loss testing was dated to of started last week and that CPS will have the ready for service on the 20th July, which the EC team at BT was also told, so if that doesn't happen there will be hell to pay LOL