My Mums' spending is out of control, I have POA with limited powers as she still has some control on her account. Any suggestions?

I thought about the pension move. But I'm limited.

The problem is that both POA are shared me and mum for dad, and me and dad for mum. I have to prove mum is not capable of managing her financial affairs and she isn't, she's spending £200 pound a week on shopping for food and tat that she buys over the phone from catalogues. Dad has a diagnosis that's no problem. I know mum has issues which need addressing and words fail me at the doctors as 'spending too much doesn't prove incapacity' but something is wrong somewhere but. Her moods are outrageous her doctor seemed casual about it, he seems to think she's just an unpleasant person. Other people see this but I'm having difficulty with professionals. I'm at my wits end everywhere I turn I hit a wall.
I only care that they can be secure.

Do you have POA over Dad too? Can you at least move his 'share' of the funds into an account Mum cannot access? Let her spend her pension etc as she sees fit, but not Dad's.

Unfortunately as long as your mom is deemed mentally competent she can spend money as she chooses. POA doesn’t give you the right or the ability to control her and override her decisions and her wishes. That is why you would have to become guardian. In the US, you wouldn’t have a chance at becoming guardian over a competent parent. Out of control spending isn’t enough to have someone declared incompetent.