It would be difficult and prohibitive for the average AME to equip his surgery with the same level of equipment as the CAA have for conducting medicals to initial Class 1 standards.
CAA have always been loathe to take a pilots livelyhood away for not meeting standards that they would have needed for the initial, which makes sense in my opinion.
As our company doctor said once, " basiclly if you can walk, talk, hear and see you have passed the Class 1 medical."