Cheers, great practical suggestions !!!

I use 'known' leads for the most part - occasionally buying reasonable value for money planet waves guitar leads from Amazon;
and slightly more expensive 'hand made' speaker leads from reputable ebay sellers.

However this big box of spares is a bit of a bugger, accumulating all sorts of cables carelessly chucked in
with the intention of sorting them all out one day, but never getting round to it.

Still at least I managed to identify one definite short speaker cable
when I took my glasses off and squinted close up enough to make out
minute printeded identification labling.