Having got a refund on the Wrongly described MachineMart set - I finally bought another set, which were delivered today. I am quite pleased with them. Franklin tools XL3870, a very comprehensive 71 piece set of 3/8" and 1/4" including normal sockets, long reach and a variety of adaptors and thin walled. They were advertised as 6point Hex sockets, but they are in fact all (except the sparkplug sockets) 'surface drive' as per Adrian's link to -
I already had two sets of 1/2" drive impact sockets, but both sets missed out the two sockets sizes I needed for the last job I tackled - so I still looking for these. The Franklin set were just to fill a gap which had been so far filled with some very old cheap rubbish sets I had. I appreciate some of the smaller sockets in the Franklin set are unlikely to be needed for cars, but I don't just work on my cars.