Hi @timcliff,
gotta hijack this comment-chain, as I am having the same issue!
Do you have the funds in your wallet to cover the fee
I have enough vests powered up, what else do i need for a fee? I didn't read anything about fees in your OP?
amounts, format of values and key must be correct, this is the only thing I can think of!
edit: nevermind, I was an idiot and I figured it out myself... sorry to steal your time ;)