Does anybody know what a sitting case is?  I just know it’s used in the realm of medicine?  Thanks.

A sitting case ambulance is one that is for non-stretcher patients. Picture at http://www.london.sja.org.uk/hackney/our_vehicles.htm

and from
http://www.kernow-lmc.co.uk/main/info/trans.html

Sitting Case: A patient who is able to make their way into the ambulance and who will be able to sit in a seat on the way to hospital. These patients should not normally be in night clothes.  
Wheelchair Case: A patient who may need assistance making their way to the ambulance and may be carried in a chair. Once in the ambulance they are normally able to sit up on the way in to hospital and do not necessarily need a stretcher. These patients are very often in night clothes and will be wrapped in blankets ambulance staff.  
Stretcher Case: These patients will normally need to be carried into the ambulance and will need to lie down on their way into hospital. They may be carried to the ambulance in a chair and then transferred to a stretcher once on board. These patients are not normally fully clothed and will be wrapped in blankets for their journey.  
Thank you! Some day I may need it in a translation.

Thank you for the most elucidating answer.  It makes a lot of sense.  My instincts said something like that, but I didn’t want to venture a guess.

BD,

Guesses are completely legitmate, as long as you identify them as such.  A guess could be right; and an incorrect guess could just as easily stir us into productive research as to send us down a misleading path.

Perry