Thank you Rowan and Lance for your replies. This is just the kind of information I was after. I'm amazed at the short service life of C4050, I guess I won't have to worry too much about weathering! She would be pretty much factory fresh. I like your theory Rowan, given its short service life, that C4050 might only have the standard RFC markings and the 79 Squadron square. I foresee no trouble in creating the serial number on white decal paper and if I come across any further evidence of a Letter I could apply it later. As you say, given the situation at the time in late March 1918 and the losses 79 Squadron suffered, the turnover of airframes wouldn't have allowed much time for squadron markings to be applied.
I have seen the Cross & Cockade book on the Dolphin, it looks great. I'm hoping they will release it as a PDF like their excellent release on the Nieuport in RFC & RNAS service. I prefer to get these publications in digital (they take up less space that way!)
On a related matter Rowan, I'm curious about the non standard markings of Dolphin C3905 of 79 Squadron flown by 2Lt Clarke on Volume 2 of you Sopwith Dolphin decal sheet. Is there a story about why they differ from the rest of the 79 Squadron markings?
Anyway gents thanks once again for your help

Dave Rickard
Rockhampton QLD