I'm sure this is possible. I'd make sure that when shopping around I was getting like for like, e.g. will other lenders leave you at interest only for the same time period as your current lender? If you research where you'd like to go, see if they offer a free or subsidised legal package/valuer. 6k is a lot so if there's a saving to be made, I'd go for it even if it was a hassle. Try running it past a broker to see if there are any other implications. Not too sure about how the institutions would view you but I imagine they'd just be delighted to take your money as long as you meet their criteria!