Hi,
Depending on the level of detail you want to know, i would start with the 'The Long, Long Trail' website. They would be able to give a basic outline of the Battalion/Regiments movements and which key battles they were involve in. If you want to go for more detail, try looking on the National Archives site to see if the war diary is available (most have been digitized now), and that will give you more day-to-day movements/activities.
As for confirmation on units. Yes the medal cards/rolls do suggest it was the 14th Battalion, but i don't know if you have seen that Ancestry also have some links to pension records on the Fold3.com website. Depending on exactly what they are (i dont have access to check) they may be able to give you more info, as he could move units (note the 14th is listed as being formed in June 1918, so he may have initially been in another unit)
Richard