I've since got a case manager in the UK who finally called on Thursday to apologise for the appalling lack of contact but she said she was unable, due to competition rules, to get any specific information from BT Openreach about what was going on and why activation kept being pushed back
What utter nonsense.
OpenReach can't favour BT in any way.
They can and do tell their ALL their customers (the ISP's, i.e BT) the reasons for delays etc.
My BT case manager was excellent as passing on the OpenReach notes to me. Often he would call me and notice there was no new updates on his notes so would put me on hold while calling OpenReach to check for updates.
I'd be pushing the case manager for an update from OpenReach. Tell them you've never heard so much nonsense in all your life and to put you through to someone who isn't pulling fiction straight out of thin air.
Cabinet still shows as available. Have you noticed if your FTTC cabinet has had an HD upgrade?
It looks like this on the larger Huawei cabinets.
Notice the small addition on the right making the cabinet a few inches wider.