Eric Bradley wrote:
It made the usual 4 or 5 beeps as when we use it normally,except that
there was no-one in the vicinity,

You didn't mention whether anyone else was in the house, or could have
been (e.g., prankish intruder).

Needless to say, we have unplugged the thing,untill we find the cause.

Occam would suggest that human involvement, however unlikely, is less
unlikely than spontaneous sequential button pushing.

--
John Miller
email address: domain, n4vu.com; username, jsm
Surplus (FSoT):
New Conn V1 double trumpet case, no logo
Tektronix 465B oscilloscope