MPs' using novelty cheques with personal or party identifiers on them to enhance their profiles and improve their electoral prospects is not covered by the concept of "private interest" as outlined in the conflict of interest code for MPs:
3(2) do[oes] not extend to cover the type of interests alleged to have been furthered in the requests under consideration. Those interests, namely the enhancement of the Members’ profiles and the improvement of their electoral prospects, are partisan political interests.
So all those Tories who used giant novelty cheques with their name on them are in the clear.
Nevertheless, Ms. Dawson finds the increasing employment of "partisan or personal identifiers in making government announcements raises concerns that should be addressed." Helpful hints as to a means of doing so are provided by way of reference to Ontario's Government Advertising Act and Alberta's Government of Alberta Communications Policy.
So there you have it.