Have looked at my Osprey book on the Paras and through my book on Arnhem but in none of the photos can you identify a medic!
I suspect that unlike the US troops the Brits just kept everything low key! In fact medics as known in the US army were not used by the British. Their medics were known as "orderlies" and certainly no one would have a red cross marked up on a helmet. Any doctor attached to the paras would have been in all probability from the Army Medical Corps and probably only wore the medical badge for the service ( the staff and snake logo). But an real expert may come along and disprove all I have said!!