Wow! What a good response to my question.
SlackAlice: - The power switch on the front just toggles between standby and full service. It doesn't actually switch the thing off, even when connected to the mains.
Connemara: - I don't know how to put a pic on here, but there is a pic on the following url:
http://www.argos.co.uk/static/Search/searchTerms/BUSH+ARDEN.htm
Everyone: - I had already looked all over the radio of course, and there are no switches other than the ones on the front, not even in the battery compartment.
Baldric: - thanks - I will check out that url you gave me. Thank you, one and all.