Dear Maggie,
I completely understand your concerns and it is a very difficult adjustment to make, all things considered. We did put padlocks on 2 of the doors, because mum lived alone and there was nobody to check on a daily basis that everything was ok. Mum wouldn't have known if anything was missing, and we didn't know the carers or meet them regularly, because we could only visit on a weekend.
We also had a safe, for all the money and valuable things, and left out a jar with petty cash for mum's weekly visit out. We asked for receipts to be left in the jar with the cash.
It seems wrong to feel suspicious of the people in whom you are trusting will look after your loved one, but better safe than sorry, was our thought. We felt so out of reach and out of control being so far away, so maybe we went a bit over the top, I don't know. However, mum had stuffed hundreds of pounds in all sorts of funny places and we had done a good search of the main reception areas, but not yet the bedrooms, so this was another reason for keeping them out of bounds.
We hadn't met many of the carers, as it wasn't the same everyday, and we were very protective of mum, who was so vulnerable, living alone and only seeing us on weekends. Reading the other posts, we probably needn't have gone to such measures, but we felt we shouldn't take any risks with any aspects of her life, so maybe that explains why we did lock the doors.
In clearing the house, we still haven't come across a few precious items. Mum's engagement ring and another one which was our Grandma's. I'm 90% sure it's probably a case of mum burying them somewhere random, but we'll possibly never know.
You have to do what makes you feel secure. But if moving the valuables to a safe will be enough, then I'm sure you'll not need to go any further than that.