I’m a care company manager OP. The company (I presume from your updates this is a carer from a CQC Registered care company, not a self employed PA) should have very clear policies on acceptance of gifts and this should have been read and signed by the carer. Breaking this is gross misconduct and financial abuse and you are right to take it seriously.
When you reported it, how detailed was the response? In my company, I would have had a documented 1:1 with the carer, got the wider team to re read the policy and sent a manager to have a chat with the client. If I couldn’t get the bottom of it (‘their word against mine’ type situation) then I would probably swap them out of that client’s care. All of this should have been communicated to you.
If you haven’t got the response you need and you feel your loved one is at risk of financial abuse from their care provider, you can complain to the CQC, the local authorities safeguarding team and finally to the ombudsman. You don’t need to have LPA for any of those complaints and they may decide to remove the care company from your loved one’s care.
You would need LPA to just march into the office and say ‘we are finding another provider’.
Talk of live-in carers is a red herring, they will have a clear plan for food allowance in their contract so everyone knows where they are. Usually about £60 a week or so.
Asking if you can have a cup of tea is fine, taking a biscuit if offered. Carers shouldn’t be accepting anything of any value at all and certainly not taking it home.
There are exceptions but they need to be clearly documented and loved ones informed. We had an elderly client with full mental capacity who wanted to give a small wedding gift to a carer (in the region of £20). The carer informed her she would have to ask the office, we informed the family who gave their blessing and the gift was given. All in the open and fine.
It’s normal for lunch/coffee out not to be paid for a carer when taking a client out.