Can't comment on the price - but the aptly-named
http://www.wires.co.uk/
does short lengths of all sorts of wire ...

Yes thanks. But so far as I could see the minimum I'd face is £10.36
(with P&P) for 50g of 0.1mm. That's roughly twice the price of a new
slicer - albeit I could then probably restring it every time it's used
for the rest of my natural

I suppose I shouldn't ask if the rest would be strong enough to deal, in
conjunction with a couple of trees on either side of the road, with the
local youfs riding unselected scooters at midnight )
--
R