The war diary of the 2nd Battalion Yorkshire Regiment is available to download from the National Archives - it will cost you £3.50.
Go to: http://www.nationalarchives.gov.uk/catalogue/search.asp
Type in Yorkshire Regiment
date range 1914 - 1920
Department code WO 95
Click on search - then scroll down the page until you find the 2nd Battalion ref: WO 95/1809
Click on that - then click on Ordering and Viewing options
Then click on View this online
You can then add it to shopping - pay your £3.50 and download it. It comes with several other units - so you will have to go thorough the records of battalions you don't want to find the one you do.
Good hunting,
jds1949
Thank you so much for this information/advice. I have accessed the war diary and it seems that Thomas Green (my great Uncle) must have died from wounds received at one of the battles of Dickebusch lake which started with gas canister attack on May 8th and then a heavy bombardment on May 9th which 'obliterated the trenches' after which 'the enemy' stormed the ridge.
The cemetery at Esquelbecq is almost 25 miles from Dickebush Lake (now Dikkebus) and there is no mention in the War Diary of survivors being transported anywhere. I've picked up snippets of information from various sites this afternoon that there were military field hospitals in Esquelbecq. (That will introduce a whole new line of research).
Thank you again - this has been invaluable help.
Best Wishes
David