Thanks for your offer Janet. I spotted your entries on the Madeley site - these have already given an indication that his unit was probably not at Ypres as the family thought - though he could have been on detachment I suppose.
According to the Commonwealth Graves Commission (www.cwgc.org), his details are :
Name: CLAGUE
Initials: W J
Nationality: United Kingdom
Rank: Private
Regiment/Service: King's Shropshire Light Infantry Unit : 1st/4th Bn.
Age: 19
Date of Death: 08/04/1918
Service No: 31486
Only son of W. J. Clague, of Vine Villa, Douglas, Isle of Man. Native of Douglas.
Casualty Type: Commonwealth War Dead
Grave/Memorial Reference: XXXIII. E. 15. ETAPLES MILITARY CEMETERY

Also, thanks to Liz - I will do some further searching - the BBC site is a good idea.
Roger