In reply to deacondeacon:
She said fellow climbers so I think she knows that, and she said swings, not rope swings.
Also, if you had two strands of dynamic rope going down 6 feet or so (at most), the stretch of that would be absolutely f*ck all so dynamic rope will be absolutely fine.
Sorry Sophie I'd help out but I still use my old ropes for the odd bit of non-climbing stuff. You do see appeals on here from people asking if anyone has old rope from time to time, usually for some craft related project or scouts or something similar. Not sure how successful they are.
Sounds like a nice initiative good luck!