In the 1914/1918 great war lincolnshire regt has a 6th (service)Battalion I was wondering what is a service battalions roll in battle

Not different from any other battalion. A Service battalion was the name given to the battalions of regiments which were formed after the outbreak of war to expand the BEF. Most regiments only had 2 battalions, and one reserve prewar, but the vast wartime expansion meant that regiments gained many more battalions.

Service battalions of infantry were raised for service in and for the duration of the war.