"David W.E. Roberts" wrote in message
...
Quick top posted guess :-)

The spare 6A breaker was for the upstairs lighting - looks the correct
rating and cable.
The 16A breaker was for the immersion - again the correct rating and
cable.

The 6a breaker failed.
Some North American horse rider with big hat and spurs decided that the
easiest way to fix things was to connect (upstairs) the immersion feed to
the lighting circuit, and connect the immersion heater to a 13A socket.

If you look hard upstairs you may find where this was done.
If so, you might be able to undo it.
i.e. replace the breaker with a new one, reconnect the lighting, reconnect
the immersion to the 16A direct feed.

As I say, this is only a guess.


That would be my *very strong* suspicion also.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)