There was no such designation as the B2A. I know this because I took the trouble to find-out! No Vulcans were retrofitted with the 301 - they remained as they emerged from the factory, either with 201's or 301's. Some 301-engined aircraft were indeed Blue Steel-capable but the vast majority of the suitably-modified aircraft were 201-series machines. Hope this helps.
Tim
(Author of The Vulcan Story and V-Bombers)