did you get the same set or the shorter ones?
i.e these ones
http://z-store.co.uk/index.cfm?fuseacti ... entCat=263
I wouldn't like to be a shop assistant when you are around
They are what I use and IMHO the long ones are the best as you can hold the knurled part to get the nut started.
Any proper extended 19 mm wheel socket 1/2 inch drive will do, but best to get one with a protected sheath on it so that you do not mark the inside of the hole again so factor in another £15.00.
Alex.