Hellp Fiona.
I have CoP deputyship for my mum, but Im not entirely clear what your concern is.
As CoP deputy you have very similar powers as POA so that you can manage her finances, pay bills etc. You can open new bank accounts and if there is property and/or investments you can manage and even sell these too. The downside is that you have to send an annual financial report (there is a form to fill in) to the CoP showing how you have managed her affairs and giving examples of how you have done things in her best interest. You also need to keep all receipts, bank statements etc in case of any queries from the court. I have not found it too hard, but then she doesnt have very complicated finances - she has a current account, a savings account, a couple of ISAS, a few shares (not worth much) and a bungalow which I have just sold. Selling the bungalow was the hardest part, but that was mostly because of the emotional attachment.
If there is no family who chooses to be the deputy, or for some reason they are not able to do it, then the court will appoint someone of their own choosing, often a solicitor. This means that you do not have to worry about that side of things as someone else will do it, but the downside is that this person has complete control over all the financial side of things and can dispose of all the belongings as they see fit eg they may decide to sell the house and just bring in a firm to clear the whole house including stuff of sentimental value that family might like to keep. They will also be responsible for buying clothes, toiletries etc and I wonder whether they will consider that persons taste in such things and nice clothes etc may not be high on their priorities. Please understand that Im not saying that all solicitors would be so inconsiderate, Im just saying that it might happen and if it did you would have no comeback. A solicitor would also charge a fee for this service.
I dont know if this helps at all. If I have misunderstood your concerns then please do correct me and Il try and address the actual problem