Yes, I have lots of tensioners for stranded

mine is just one 1mm? strand

They're typically a
rather crude ratchet mechanism.

See, for example, at http://www.tanton.ltd.uk/, look under Electric
Fencing accessories.

Or:-
http://www.mcveighparker.co.uk/acata..._sundries.html

Those will I'm sure will be ideal when I have sussed out how on earth
they work. I imagined trying to use something massive and unwieldy in
a tight space but at that price they can't be very big. How big are
they?

Anna

~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642