I believe the occasion is a wedding as the ladies in the photograph are wearing corsages.Unfortunately the name Trigg does not mean anything to me but i can confirm that the lady on the right in the dark coat is my grandmother Charlotte Ashmead (nee Knight)who was married to Henry Ashmead - he can just be seen at the back of the ladies. Interestingly I also have a photo of Henry and Charlotte together in front of the same backdrop which appears to have been taken on that day. I would be intersted to find out who's wedding this was and what year as i believe there were a lot of Knights living in and around Cinderford at this time.