Thanks for the heads up Trevor, it would cost a fair bit to stock up at those prices. I seem to remember that the fretwork spade drills or something similar was used in watchmaking, these were known as forrets(?. seems that they are defunct now.
My last purchase of fretwork spade drills was 40 years ago. I got them from a local ironmongers (now long since gone). They were probably "old stock" even then.
Looks like I will make some, as it doesn't look too difficult. I have found that the archimedian drill and the spade drills were very easy to use, much better than other options at the time. The pre war Herbert high speed drill that i restored 18 months ago, may well be a better bet now.
Andrew.