vintage (1990s?) women's shorts, need new elastic (Cambuskenneth FK9)

Vintage (? 1990s?) womens baggy shorts, size M, with pockets, 52cm long. Elastic stopped working but the repair started years ago only got as far as pinning on tape to make a tunnel to run new elastic through. Otherwise in good condition, nice bright colours - turquoise, red, purple, mustard. They've sat in a bag in a cupboard far too long so I hope someone can finish the repair and wear them.