This is not constant, it began this morning, continued for an hour or so and has now stopped.
There's a new boiler, programmer and associated technology in the revised hot water/ch installation which I'm happy to describe if asked for details but I don't know what might be relevant. The (diy) installation was completed a couple of days ago and, as far as we know, didn't affect the radios before. They're playing in all rooms all day long so we would have noticed it.
The timing of the radio interference - on every radio in the house (we don't have a tv) - is exactly the same as the 'ticking' of the valve, which is a Honeywell V4073
Can anyone suggest a cause, please? And if so, a remedy?
TIA
Mary