Known as a 'Tapping battery' condition .............. the problem with remote testing is it is a one-shot event, ie: it takes the readings at the second in time. The very next second, the battery contact may appear again !!
Couple of points, I wouldn't be overly worried that your circuit will fail before Xmas ........ if it was a large battery contact it would affect your circuit in the here and now, so it must be a very small contact fault.
Also, I don't know where you get the notion no-one is about at Xmas ??. We are allowed 1 day off (as well as the 3 BH's). The order books are closed completely*, so faulting is all we do, hence it should be easier to have us attend site ??
* This has always been the case in years gone by, whether that changes this year is above my pay-grade.