FFF last two being fridge freezer

I have I had many problems with my Thetford fridge freezer it is less than 5 years old but pretty much every winter develops a problem, so much so that we carry a plug in cool box. On Friday it stopped cooling on gas and ehu, based on a recommendation I called a chap called called Wayne https://www.stayonthemove.com/contact.php a mobile technician who came to my pitch a hour later. He tried a few things but basically he thought the ammonia wasn’t getting through, an essential element to cool the fridge freezer on gas or ehu. He said see if it starts working overnight but if not he’ll take the fridge freezer out and turn it upside down. If this doesn’t work then I need a new fridge freezer.
Anyway no luck overnight so on Saturday so Wayne came back, fridge is turned over left to stand upside down for a while then turned back up right left to stand again. After a few hours turned on the fridge and it started cooling. The freezer was minus 18 this morning.
It may pack up again but at least it’s working at the moment.
Wayne is British and covers quite a big area in Spain. Highly recommended if you have problems with your camper in Torrox Motril Malaga area.

Jamie, has you'd fridge stood unused at home for any long periods over the last year,?
I'm wondering, has an unused or regularly used fridge anything to do with problem. I've heard of the fix several times but haven't seen any history of the fridges before the problem started.

Is it a manufacturing/design quality issue with the modern units. A friend of mine is on his third fridge freezer, under warranty conditions, in a new van he took delivery of a few years ago.
My old 2005 fridge freezer has never missed a beat , except for in 2019 when it needed its burned-out burner replaced.
It has alway kept the beers cool and the burgers frozen at ambient temperatures up to 40°C and has alway been turned off when at home.