as far as i remember this argument was put forward and rejected by the royal colleges. However most military hospitals near the end were filled with NHS patients anyway.
To be honest i don't think the argument stands up the current system was designed to train doctors and medical staff for ops they should therefore be in trauma centres around the UK not the district general hospitals most of the MDHU's are located in.
A few other solutions could work better re open the military hospital for nursing and professions allied to medicine and keep a strong link with the major hospitals and don't employ doctors as full time forces have them as TA/RNR/RAFR/Aux and employ them on an FTRS basis but support them in their continuing medical training as a retainer and a lever to get them to go operational and let them be out in the big NHS.