Hi there, as far as I'm aware, there were three Dalby boys, James, William and Johnny.
James (kia 26/04/15) is number 24 on this photo. I believe William is number 45, identified by his nephew Ronald?
Derek (Derilda?) identified Johnny as third from the left, back row, does this make Johnny number 2?
http://www.fusilier.co.uk/old_photos..._fusiliers.htm
Interestingly, another descendent J T Dalby was one of the 'secret seven', in other words one of the Chevington Auxilliers in World War Two mentioned elsewhere on another thread.
There seems to be a batch of stuff relating to the Dalbys in the Woodhorn archives, one photograph which appears to include your relative Herbert Goward Janwhin?