Mortgage when on benefits

Hi I just wondered if anyone had managed to get a mortgage whilst on benefits and 100% of their income being from benefits. I’ve been given an agreement in principle with Barclays - although they had to do some tinkering with the things on their side so I could get the email in writing. But they are fully aware all my income is from benefits (income comparable to full time work). I just don’t want to go through the hassle of it all if they still end up rejecting me when my application goes through. Thanks