Remortgaging and equity release

I am due to do remortgage and I found it incredibly difficult to find an interest-only deal.

OK, I have to have repayment mortgage but I want everything I paid over two years back when I remortgage, leaving exactly 25% and not a penny more. But this seems to be difficult too. When I say to mortgage lenders that I need to do equity release, they say OK, you can just have a secured loan on top of your mortgage, and even at the same interest rate and the mortgage. But I suspect a catch here, they may probably change an interest rate or this loan will restrict my access to other loans etc. How can I just make a new lender accept 75% LTV mortgage and send the rest back straight into my current account without asking me what I need this cash for?

To those wondering why I want interest only mortgage: I believe more debt (at interest rate lower than real inflation) is better, provided this debt is an asset. And there is no much point in saving or repaying mortgage as government will print more money sooner or later, so let it burn its own money than the ones I earned.