Thanks to G0MRF/G3NYK/G3YXM & GW4ALG for prompt replies.

Steve, GW4ALG wrote
.

While you still have that rogue LF transmitter (cleverly disguised

as a TV
receiver), is there any chance of doing some quick tests for future
reference?  For example:
- does the noise reduce when you unplug the TV antenna? <<<<<<<<<<  NO.
- does switching the TV to 'standby' make any difference?<<<<<<<<<<<YES-it
disappears.
- does the noise appear to be conducted via the mains lead, to the house
wiring?<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<YES

It would seem that Alan,s approach( sent by direct e mail) of trying a mains
filter is the first line of attack. In the meantime I will advise the dealer
that it is causing interference with "Long Wave "reception!
Thanks to all
Best regards

Mike GW4HXO.