Thank you all very much for your kind comments. Sorting out this radio has actually re-kindled some of my old interest in short wave listening, away from the amateur bands!
Oh, and I'm pretty confident that the intermittent faults have hopefully gone for good, too. I've had this set running for many hours now, and apart from the drift - which incidentally seems to be related to mains voltage as much as anything - the radio has performed perfectly. But please don't tell it I said so...
