Hello David,
I also get my wire which I use for shrouds and stays on my thames barges from the site below, Harrissportsmail, an on-line fishing tackle company. They sell 7 and 49 strand wire for traces and it is also coloured, brown, green or the usual grey, The 49 strand wire does not kink, and you can tue knots in it!
here's a link HarrisSportsmail.com which I hope works.
Elastic may well look the part, but when it ages?
Hope this helps, Kimosubby