Dr Beat:As i want to avoid a recurrence, i have now bought the RA Superclamp, now attached, as Peter Bevir of RA suggested, to my Tacima 929. Though the RA Superblock, with built in fuse and each socket is individually Superclamp-ed looks better suited for my purpose, but at 440 quid, it's a lot money for an 8 point extension.
A Superclamp is nothing more than a VDR (Voltage Dropping Resistor). Your Tacima already offers that same protection. The Superblock (you mean the Powerblock?) offers only a different type of that same protection (Megaclamp), nothing more. I think you'd be spending £440 needlessly. Your Tacima hasn't prevented the problem, so it's not a spike event causing it, and a £440 Powerblock with a Megaclamp won't change that. And neither will an extra fuse.
Dr Beat:The power company did not appear to be using any fancy bits when they were "testing" my mains
They should be using a power quality analysier, a hand-held digital device, similar to this:
http://www.fluke.co.uk/comx/portal_gen.aspx?locale=uken&page=pqt. If they weren't, I'd call them out again, and tell them to bring one with them.
Dr Beat:So, i have decided to call a proper electrician (a private contractor) to check the mains again. Perhaps he can then argue on my behalf with the power company chap. Almost like calling you over to check my mains..
Well, I am a qualified electrician, and I do install a number of dedicated mains circuits for Hi-Fi and AV enthusiasts. I already have in excess of £3,000 of the best quality electrical test instruments, but I don't have one of these (and I doubt your private contractor will either): they're just too expensive to justify purchasing for occasional use:
http://www.fluke.co.uk/comx/show_product.aspx?locale=uken&pid=37819. They record all anomalies on your mains over a period of time, which can then be downloaded onto a computer to see when and where the problems occured. Unless your electrician is fortunate enough to own some kind of power quality analyser, I again think you'd be wasting your money: He can't tell you anything new without one. It's the electricity providers that own these expensive devices!
You seem convinced that the problem is with your mains, and I'm afraid, from the information you've given, I don't share that view. Frankly, if such a severe event were happening on your mains supply, there's a very strong chance that more than just your power amplifier would have failed. Hence my feeling is that the problem remains with your amplifier. As a minimum, I would be insisting that Cyrus should be replacing the power supply - at least that dodgy fault detection circuit - not continually patching it back together.
But good luck Dr Beat. It's a frustrating problem. I hope you get to the bottom of it.