Yup, I found three or four of them rummaging through the boxes on the surplus tool stall on Haslinden carboot. After the novelty of owning the first wore off I realised I'd never actually use it as I didn't mind carrying a full sized brace if I was carrying the roll of bits so I passed it on to someone who would, and the subsequent ones I found. Unless he brings some new boxes from the mill where there's a supposedly a vast amount of kit dumped I've picked him clean I'm afraid. I know I paid a pittance for them.
ATB
Tom
Ps when these adapters were originally discussed I think some one pointed out that that other perennial find at car boots the old tap ( as in taps and dies , not sinks ) handle would also hold a brace bit if suitably large.