As a previous poster has stated 'take a picture of your boat with the background enviroment', normally phone photo's are date/time marked;
(save the last 6 month photo's to a hard drive'), if and when these letter's come just smile if you know your within the rules.
If you know you are sticking to the rules these sorts of letters would become less stressfull because you woul be able to fight your own corner with a smile.
Extra onto post : CRT need to make the rules black and white and understandable by everyone who can understand basic information, i do find the rules and regulations rather 'Enrypted'. maybe even trip and fail provoking.