Were the AP responsible for medical issues? There was an AP a PD and a Fixer. The Fixers helped helped at the Borders if that was required. As far as possible they didn’t but they did have to intervene sometimes. Sometimes there were Carnet problems.
Were there any “red lines” where the plug would have to be pulled if things had gone wrong? Definitely when you were told you were no longer insured! They listened to safety advice, e.g. being out after dark.
Was it an environmental show? No, not specifically.
The size of the support team? Each team had an AP/PD along with a Fixer. In London there was an executive producer and a “story team“.
The rushes were picked up at the checkpoint. Rushes runners to DIT.