The U.S. National Archives database of WW II POWs lists Matt Brazil as having been a prisoner, but the record doesn’t include a camp name.
A couple of things mentioned in Laura Rawson’s article, “The Story of Sergeant Matt Brazil….,” and the Fog Horn article seem to reinforce that he was in Camp 59:
The article above mentions two British doctors. The two British doctors in Camp 59 were J. H. Derek Millar and Adrian Duff, both Scottish. The article also mentions a dentist—who was named Hogson, according to Giuseppe Millozzi.
Matt mentions getting mail regularly, which was not true in all camps.
Camp 59, though not in Ancona, is near to it. Matt’s estimate of their being around 1,300 prisoners (about 1,100 British and 200 Americans) in camp is close. The number in Camp 59 at the time of the escape is generally estimated at 2,000. Giuseppe Millozzi refers to Italian military authority records in giving the count of prisoners in March 1943—close to the time Matt would have arrived there—as 1,445 British and 464 Americans.