Bamboo v6 didn't have support for webhooks but there was a plugin that provided that functionality and allowed triggering of a webhook post deployment of each deployment plan/env.
Bamboo v7 does have support for webhook and even has an out-of-the-box 'Deploy webhook' template but it seems only to be triggerable as part of the build plan/jobs and not the deployment plan/envs. There is no equivalent plugin for v7.
Any ideas on the best way to do this?