Question Author
Thanks westere....I am now able to understand what's happening.
For your info. the appliance ( over 20yr old Hoover Fridge Freezer.) has always been positioned in a corner alcove with only about two inches of space all around it. You could say that it's in a ventilated cupboard.
In fact, I've always been a little proud that, personally, I built a small storage area above the appliance and enclosed the FF behind a door, which, in keeping with the kitchen, resembles a piece of timber studded wall and is opened by a lift-up horse brass.
I can now appreciate that the ambience around the FF is not ideal and, having said that, I must now prepare for the day that the oldie worldie appliance gives up the ghost and goes completely cold!!
Best wishes....(to both of us!!)........Ron.