Yesterday afternoon a fishy smell started appearing in the back
bedroom, and being a bit clever, we ID'd this straight away as dodgy
electrics.

Finding the root cause was a big problem, and I got up in the loft to
see if anything amiss there, checked out the various plugs etc, and
came to the conclusion that it was probably the light fitting, which
was a bit warm to the touch.

Turned it off, with a plan to get a new fitting tommorow, but the
smell persisted. As it was now Sun evening, and even Q&B closed, I
decided to remove the pendant from the ceiling.

Later that evening the smell was becoming intense, a horrible fishy
smell.

At this point we saw the shells the youngest son had brought back from
the beach the other day, one of which turned out to be a West Mersea
oyster, which had been alive, and closed up, when he brought it in the
house a few days ago. Now it was opening up, and it was clearly the
source of the foul fishy smell....

Doh!