Hi Bron
I saw some of these at Bedworth Fest, and just got Mark to read me out the advert from the program. As follows:

Table mounte3d supports for necked instruments. Made by a company called Briarmill.

Mail order :
Send a cheque for £11.95 made out to Briarmill.
Address is : PO Box 35 Ashton-u-lyne Lancs OL7 9FJ
Tel: 0161 3304555

You'd need to give your name, address and phone number. Also specify which logo you want on the pouch it comes in (out of 'pub-prop' or 'table-top prop').

That's one option anyway. May not be the one you've seen, but they looked OK on the stall. Basically a sort of clamp thing to attach to the table & a gated thingy to bung the neck of the instrument into.

Probably best to give them a ring...

Kris