And flew this year only as a private pilot. My examiner told me today that doing so was okay, though that rule would change. She told me that in the future if your Cat 1 period was exceeded, you would not revert to a Cat 3, just your Cat 1 would not be valid anymore, and you would not have a valid medical. If you wanted to change from Cat 1 to Cat 3, and get an extra year, you'd have to apply for the change. That was the extent of her explanation.(6.3) The holder of a commercial pilot licence or an airline transport pilot licence may exercise the privileges of a private pilot licence until the end of the applicable validity period for the private pilot licence specified in subsection (6).
So that's all I know about that, but just so you're paying attention, should you choose to exercise that privilege in the future, check the regs....