This John Worsdall did not go overseas before the beginning of 1916 (no Star awarded).
If you can access Ancestry, check to see if his service record has survived, but be aware that about 70% were destroyed. If there is no service record, try finding men with similar numbers. That will at least give you some idea when he joined. The actual medal rolls at Kew should give you his battalion.
What I cannot see is any mention of the SWB, which may be on another card, but not usually.
If I had to make a guess, I would say that he was a late 1917 reinforcement, possibly to 1/5th Battalion. That is based purely on the half a dozen casualties on SDGW with similar numbers.
Phil