I volunteer at Purbeck Marine Wildlife Reserve at Kimmeridge in Dorset. We collect and record balloons and write to the originators of any we can identify to let them know about the impact and ask them not to release any more.
We have had some very postive results and responses so it is worth a go. I'm a member of MCS as well and their "Don't Let Go" info packs are great to help you campaign against balloons releases.
