6 days & 23hrs later, @BTCare releases me back into the community ...

By which I refer to resumption of my voice telephonic service and consequent stable synch of the broadband connection.

The Friday line diagnostic first test seemed to indicate an issue at the exchange. The Tuesday second test indicated a likely fault within my premises, requiring an engineer's inspection scheduling. Eventually on-site this afternoon, that Openreach engineer instead tracked the fault to a "loosened connection at the local junction"; and he proved polite & efficient. As an unrelated aside, I note that another Openreach engineer was attending the local junction last Friday "working on a neighbour's line" at the time my fault initiated.

As a point of general information, I found the only effective form of interaction with BT in this matter to have been via their Line Fault webpage at https://www.bt.com/consumerFaultTracking/public/faults/tracking.do?pageId=2 ; as verbal reporting of the problem to the Indian/Pakistani Customer Service Representatives, via the Nos 800800150 & 03301234150, left me uninformed as to the progress of the case. Supposed sms updates were never received, except for two [both 2hrs after the respective events]: we acknowledge your fault/we've fixed your fault. Rather important ones, such as we need you to schedule an engineer's visit to your property were never received.

If not for the backup "handset as modem" broadband connection [yes, that previously-described congested one dependent on the intermittently-functional local T-Mobile Uk mast], I'd still be waiting - a week on - to learn that BT was waiting rather on me to book an Openreach appointment to investigate my case, instead of actually having had it resolved. *fingers crossed*

So, if the fix proves temporary ? Well, I'll be taking up the offer of intercession from the @BTCare twitter staff; and be establishing whether BT's 21st century social medium can assist its 19th century one.