Ah...my cooker doesn't have that facility.Like most any kitchen oven out there I assume your oven has an "on" thermostat light. As long as it doesn't come on too frequently it is maintaining your pre-set temp pretty well. You're burning gas only when that thermostat/indicator light is on.
I am exploring other ways of finding this the info in my OP. It's not a burning issue but it would be nice to know the answer since it is stopping me trying out some long slow oven cooking recipes.