Started this today. Didn't get far as I couldn't find my stubby triple square M14 socket, but found the longer one which I know is too long. Lost all my patience within 2 mins of not finding the socket and then attacked it with a Dremel, which wasn't really successful.
Going to go at it with some tin snips tomorrow - it's so rusted it's flapping about so think I can get in there with some snips. Basically going for a bodge!