I don't see how opening a new account, with limited transactions is going to cost you much, other than perhaps a little time & given your previous referances to concerns about achieving better exchange rates, can't see why you would not be willing to myself ?
Can't say for sure, but I doubt it would be very much if anything. To the best of my knowledge, they would use a demand deposit account, which may have a minimum opening balance, but not a minimum balance to keep it open.
Hi G - Anglo confirmed they have a minimum balance of $2k and a 'wide spread' on their USD/EUR FX rates, so I don't think that will be much use to me. Awaiting response from BOS now.