Ok, heads-up on my e-calls only issue.
Whilst there may be several malfunctions that cause this - blacklisted aside - I have finally gotten a brief report back from the outsourced Samsung repair company. Though I have yet to receive a detailed engineers report )won't hold my breath!) the company say there was some kind of software fault that they could not rectify and opted to replace the PBA (motherboard).
Now, from what I've seen on the net, this seems to be a regular proceedure for assigned repairers: can't sort it, so just replace the motherboard. If this is the case with mine, then I won't see any detailed report.
As a caveat, do not accept any repair companies telling you your phone can't be 'economically repaired' and just sent back to you with a 'sorry' letter. Take the case up, like I did, with the CEO of Samsung in your country; then you'll get some action done on your phone!
I will update if I ever do get an engineer's report.