G'Day from Sydney, Margaret.
I too, had a Great Uncle who fought at Passchendaele on the 6th of Nov, 1917. He was with the 28th Battalion, which was a Regina based Unit. The 26th also fought at Passchendaele that same day, but on the far right of the 28th.
Unfortunately my Great Uncle 267104 PTE R.F. Allen was hit by enemy fire in both legs, and left arm early in the fray (some reports list the wounds as GSWs (gun shot wounds) and another as SW (shrapnels wounds). It was a difficult evacuation under constant small arms fire, and with the mud and all, but for him, he kept his humour up, joking around, saying 'it looks like I am going home boys".
He was removed from the area by SB's and ended up at N0. 3 CCS near Rouen, where both legs and left arms were amputated. He was given morphine for the pain and died of his wounds the next day. He was 21, and never made it back to the Quill Lake District of Saskatchewan, where we (my family) come from.
As for the 28th, they reached their objective that day by 0900, and held it until relieved. It took a fair bit of research (even finding out what the METREP was that day, right down to the temperature), and I managed to find an old Vet in the Quill Lake District, back in the late 1970s who was present and knew Robert well (they had all joined up together in Wadena, Saskatchewan [214 Batt'n, Wadena Wildcats] in Jan 1916) when they were evacuating Robert out of the line.
I had also wrote to Vets Affairs and I got a complete copy of his service record, and the location of his burial. I have read many books, including Dancocks Legacy of Valour, The Canadians at Passchendaele, ISBN 0-88830-305-X. After just having a quick squizz, it lists the 26th, and what they did during the battle. Its out of print now, but you should be able to find a copy.
Good luck in reseaching your Great Uncle Jack.
Regards,
Wes