This is cropped from a corner of a photo of the instrument panel in the Wessex HAS Mk1 at Duxford. I haven't flown a Mk 1 for well over 40 years but I don't recall two JPT gauges. Having said that, I sat in the cockpit at Duxford for a good 15 minutes and took this photo and never noticed there were two on XS863......
This photo of a Wessex Mk3 panel shows only one JPT gauge: