My 7 year old ids completely toilet trained day and night but she insists on wearing training pants to bed . tried all ways but she becomes very distressed at the thought of not wearing one
I would not worry. I would let the child have her training pants if she feels comfort in that. I would allow her even to use the same training pants for a few nights in a row (if clean) and suggesting she use the training pants over some underpants in order for them to keep clean longer.
I would try to start treating the training pants like any other clothing, and try to keep the same one in the room (again only if clean), letting it become old and broken.