Having sourced the dowels for the drawers from a model boat shop, the unusual wood suppliers continued with the runners coming from Dolls Domain, a business which as you might guess supplies the dolls house hobby. Some 15mm square hardwood would do the job I reckoned and anyway the local hardware store couldn't help and there's no way I wanted something wonky from a DIY supershed.
In the wood corner of the shop these were many sizes for not very much cash. I bought three on the basis that I'm sure the extra would come in handy one day. How much modellers detritus is born from this thought ?
Anyway, once cut to length the runners are fitted to the side of the case. No measuring for me, I just put the drawer in, then a bit of 1mm plastic to give a touch of "slop" and then the wooden runner. To make the PVA grip properly I piled some tins of varnish and then a pot of lead shot on top. One runner at a time the process takes several hours but then I'm not in a hurry and this is the bit where it can all go wrong. If those drawers don't slide I'll feel pretty stupid.