From what I have heard of Potter's symphonic output I would say he was a rather distinguished symphonist. The UK COPAC does not list scores of the F major, D major (except in a 2-piano version) or either of the C minor symphonies broadcast by the BBC - though, obviously the orchestral material for these exists somewhere and the BBC or Davan Whetton would doubtless be able to direct anyone interested to it. RAM, however, has a symphony in B flat by Potter (1839), which would bring the total of his extant symphonies to 7. I think it would be very useful if we could hear a cycle of all these; I have no doubt it would provide much pleasure to members of this forum.