"
The Battles of the Somme, 1916" covers the whole period from 1 July to 18 November.
http://regimentalrogue.com/battlehonours/firstworldwar-btlhnrslist2.htm
8 Oct can be narrowed down to the specific actions:
(viii)
Battle of le Transloy Ridge. 1-18 October
Included tactical incident:
Capture of Eaucourt l’Abbaye.
(ix)
Battle of The Ancre Heights. 1 October - 11 November
Included tactical incident:
Capture of Regina Trench.
Henry Boucher's Circumstances of Death record:
http://data2.collectionscanada.gc.ca/microform/data2/dm13/d13/006003/31829_B016721/jpg/31829_B016721-00172.jpg
58th Battalion War Diary:
http://data4.collectionscanada.ca/netacgi/nph-brs?s1=58th+battalion&s13=&s12=&l=20&s9=RG9&s7=9-52&Sect1=IMAGE&Sect2=THESOFF&Sect4=AND&Sect5=WARDPEN&Sect6=HITOFF&d=FIND&p=1&u=http://www.collectionscanada.gc.ca/archivianet/02015202_e.html&r=1&f=G
8 Oct 1916
http://data2.collectionscanada.ca/e/e045/e001118307.jpg
http://data2.collectionscanada.ca/e/e045/e001118308.jpg
http://data2.collectionscanada.ca/e/e045/e001118309.jpg
http://data2.collectionscanada.ca/e/e045/e001118310.jpg
http://data2.collectionscanada.ca/e/e045/e001118311.jpg
My series of pages here may be helpful in your further research:
Researching Canadian Soldiers of the First World War