I cannot answer your question about prison sentences but during WWI, employers, in some cases, sought exemption or temporary exemption for an employee who they felt was essential for their business. In the one case of conscientious objection of which I have read, the person agreed to serve in a non-combatant role, i.e. the Royal Army Medical Corps. If you are looking for a particular person, I suggest a trawl through the local paper but someone else may know of a list of conscientious objectors (or "conchies" as they were termed) who were imprisoned.
Isles.