Found: service case, plastic, containing selection of bolts
Steve and I came away from Brands Hatch with a yellow plastic service case, transparent top, full of bolts of varous sizes. It is a bigger than normal one, probably 30 by 40 centimetres and 8 deep. It turns out to be neither Richard Mallock's nor Peter Burnham's (who were sharing a garage with us). Was it yours? It's presently at Mallock Sports waiting for an owner to claim it.