J&L have chucks and part-finished backplates for sale, including in the latter category L-zero which fit the colchie student.
The backplates are by toolmex, and from the picture it has the L-zero fitting, 6 counterbored holes and 3 threaded holes. I imagine the 6 holes correspond to the mounting holes for the toolmex chucks of the corresponding sizes.
Are the toolmex chucks any good? Is it worth the extra hundred or so quid for the high-precsion model?
They don't quote typical precision values for either of 'em. mind, the comment about backplates may be a red herring, as it says "other mounts available", so it might be that they make a specific L-0 one, it's quite a common fitting, although I suspect a bit out of date.