Checking the Commonwealth War Graves, I see he is buried at Etaples British Military Cemetery. Etaples, a French coastal town, was the site of many military Hospitals during WW1. So, even though Henry Worrall died of wounds in a hospital at Etaples, it is hard to say what date he received his wound. The 1/8th Warwicks served in the 48th Division. The the Division was involved in the Battles of Passchendaele (3rd Ypres) during the late summer and autumn of 1917. The division was not involved in the opening of the offensive on 31 July but started to see action from the middle of August. The 1/8 Warwicks took part in an attack on 26 August and again on 4 October.
If he was wounded in the August, I would say he would have reached a hospital in England. Thus, I would favour the 4 October action when he received his wound. The Division was attacking towards a village called St Julien, south-east of Poelcapelle. Please, put out of your mind the thought of men climbing out of trenches crossing No Man's Land. By October, 1917, the battlefield around Passchendaele was a waterlogged moonscape and St julien was just a brick stain in the quagmire that the men had to wade through to attack the German pill-boxes.
There is an excellent book entitled 'Some Desperate Glory' (ISBN 0 85052 840 2) it is the Diary of a young Officer, Edwin Campion Vaughan, who got posted to the 1/8th Warwicks in January 1917 and was wounded at the end of August 1917. It gives you an insight of what the battalion was doing and the conditions it fought over at Passchendaele.
Any more info let me know
Terry