The taxon dictionary in Recorder is based on the Species Dictionary managed by the Natural History Museum in London. Requests for changes should be made in the Species Dictionary section of the Recorder Forum, part of the NBN Forum.
The biotope dictionary is managed by JNCC.
When the NHM or JNCC make changes they will be made available to Recorder users as dictionary upgrades which you will be able to incorporate into your system by running a dictionary upgrade.