Why? She can’t do anything; only fraud police can.
the only thing she’ll do is use it for a photo opportunity
If there's a significant crime in progress, drawing as much attention to it as fast as possible is the right thing to do. Yes, an MP or member of the city council can't make an arrest, but they can point out "issues of concern" to those who do have the authority to throw more resources into an investigation.
It may also be worth calling the press on this. If they run a story about this, more people will come forward.
Personally, I haven't yet seen a case with an evil mastermind behind a frontman who pretends to be a trading guru and likes to show off expensive cars. I'm not saying it's impossible, but I've seen more than enough Ponzis unravel to know it's highly unusual.
Running a Ponzi scheme isn't brain surgery. Charles Ponzu kept client records on index cards. It would be VERY simple to create an Excel file to track all the money (real money and fake claims of money). I'll wager someone out there even sells a template for it.
Overall, the theory sounds more like a way to try to divert blame. The claim the FCA shut down his account and that the banks froze the accounts could easily be designed to give more time to transfer the money away for a thorough run through the laundry. Or, he could say "All resolved. Go ahead and deposit more now and withdrawals will be available in a week."
No matter what, don't sit back and wait. Talk to your bank. If you happen to have your account with the same banking firm he's with, talk to your bank even more. If you transferred or received money via PayPal, talk to them. Give every scrap of info you have to the SFO, the FCA, and the nearest police station with a fraud department. Tell your MP. Tell the mayor. Tell the city council. Tell the newspapers. Tell the TV stations.
Don't give up. You may have lost a significant percent of your funds, but if you can keep the remaining money from ending up in a safe deposit box in the Caribbean, you have a chance to get at least some of it back.