What happens when police do a welfare check?

From a first hand perspective, I have had a welfare check done on me. Basically I left a pretty dangerous situation and was in the process of changing names, etc. Part of that meant I was living in temporary accommodation in a different area and was laying quite low. I was also working cash in hand for a builder. One day I came back to see a police car outside the house. They had been to the door and as I was going under a new identity, the other people in the house had rightly said that they had never heard of me. But they waited anyway. I really don't know how they pinpointed me down to that exact address, but there we have it. I can only assume it was a car I was using at that point which was registered with the DVLA under my old name as my new name was not yet legalised. Anyway they came up to me and asked me my name, etc. They said why they were there and briefly asked me about my situation. I just said I was between jobs, between addresses but was perfectly fine. They did tell me it was my ex who had raised concerns for my welfare (i.e. getting the police to confirm where I was so she could re-establish what she was up to). I said categorically I did not want it confirmed back to her where I was. They really treated it like a joke and that it wasn't important. As I didn't want to get in details they were almost taking the piss. The next day, I saw a couple of very familiar cars around, basically her and her 'ave a go mates' vehicles. It was cool, I just left and didn't return. But it was obvious that the police ignored everything I said that I didn't want my location confirmed, the whole nine yards. The guy I was working cash in hand for even mentioned that someone had come in looking for me. So yeah, the police confirmed everything as they asked where I was working. FWIW, I did drive about 120 miles away to my next planned location. It was a bit earlier than I ideally wanted as I was still getting ducks in a row, but something I was planning to do anyway. I weighed in the car at a scrappy en route as was my plan originally. There were a lot of reasons for full on disappearing even from my own family. And it's a history I'm happy to leave behind. But sorry to confirm that yes, police welfare checks can indeed be weaponised if someone has a mind to do so. The police will absolutely think nothing of confirming location and whereabouts to whomever raised the welfare concern to them, even if you specifically ask them not to. At least, the cops who attended my address did anyway. I don't know the situation between you and your Mum. I don't know if she is able to trigger child protection visits. My Sister is the only person in my past that I have any contact with whatsoever, very much a closed secret from my any family members (in reality, she has little to do with our Mother either). However her son went through an incident where upon the school decided social services had to investigate her. It was all very torturous and remains to be so. Though the child is doing better now after the incident he went through, it is in no part thanks to social services, neither my Sister nor the boy want them around and in my opinion it was never ever needed. He's been seeing a child psychologist since his incident which has helped him far far more. Whether your Mum can actively trigger such an investigation, I have no idea. If she does, then she does. All you can do is present your family life as it is. Maybe they will back off, maybe they won't. I'm really not in a position to say. It is sad that people can use these sorts of services to screw with you if they so wanted. But to answer your main question, the police shouldn't but they probably will.