Thanks again for advice everyone - I have now obtained a handful of
variously sized straddle cables from friends who recycle bikes (shameless
plug: lets hear it for the excellent Cyclemagic in Leicester,
www.cyclemagic.org.uk)
Oddly, the Viscount brakes do not quite take Weinmann nipples, which are
about 1mm too thick. A little judicious drilling and filing was necessary.
All fine now.
Also oddly, the cables I removed were longer, and had globular nipples (!!).
Looked like long thin dumbells. What could they be?
Possible alternative to tracking down Weinmanns: Shimano cantilever cables
(the sort where you require two to make up the whole straddle) are almost
exactly the size and shape of the Weinmanns, and may be easier to find.
Also, an old-style LBS said; "we can always make some for you" 'You can??' I
replied incredulously. 'Of course we can' they replied. So worth trying.
And thanks those who warned me - I am VERY aware of the Viscount fork
problems: on this bike, the forks have been replaced.
best wishes
Nick Jones