I can appreciate your frustration as I think us medal collectors tend to expect everyone who came close to a campaign to earn at least something, apart from sunstroke that is!
In fact, the 1st Bn. Yorkshire Regt. did participate in the Battle of Ginnis and General Order 68 of 1 June 1886 stated that all those not already in possession of the Egypt Medal would receive an undated one without a clasp if they had ... served at and to the south of Wady Halfa, between the 30th November, 1885 and 1 january, 1886, both dates inclusive. As I'm sure you know, there are many reasons why a soldier might not accompany his bn. when it deployed; he could have been in hospital or on detached duty, or part of another detachment. You mentioned that he had enteric fever and this may have left him too debilitated to have accompanied the main body when they left.
Whilst it may not mention a medal in his WO97 papers, it might be a good idea to consult the actual medal roll to confirm the non-issue ... or not. The medal rolls are available at The National Archives at Kew but can also be viewed on-line through Ancestry.uk.co if you have a subscription, which, sadly, I do not. Pte. Woollen may very well have earned the Egypt Medal, and the Khedive's Star, so you may want to verify this on the roll just to be certain. Good luck!