Harry Bloomfield wrote:
Lobster presented the following explanation :

Bingo! Sorted; thanks very much.

Do you know what would have prompted this behaviour? I'm sure that in
the past if ever I've disconnected the power, the unit switched on
silently, asking for the code immediately.


Cold weather, high cranking current, lots of voltage drop and perhaps an
almost flat battery as a result... The radio perhaps thought it had been
disconnected from the battery briefly.

Sure, that would make sense, but I'd have expected totally different
symptoms than what I saw (as per my last post); if I'd experienced those
I'd have sussed the problem immediately!

David