If you look at the "official" Deer Stalking Certificates that are run to a nationally recognised standard then there are only level 1 and level 2. Level 1 is a prerequisite for level 2.
Beyond that people can choose other courses such as the "Deer Manager" course that BDS and others run. These are not, strictly speaking, stalking qualifications as they cover a wider variety of topics and there are no prerequisites to taking them. That doesn't stop many stalkers choosing to study for them, however.
Bear in mind that these type of qualifications are voluntary only, as we don't have mandatory hunter's training in the UK yet, even if some might like to treat it as such. For sure there are more deer stalkers in the UK that the 23,000 who have completed Level 1!
How is it in Canada?