While your likely definition of continuous cruiser was lifted from the Act, BW's wasn't. Their one involves such things as being engaged in a continuous progressive journey around all, or a significant part of, the system and not returning to the same area within a period of time. Concepts which do not appear in any legislation. I agree with you that the legislation appears quite clear. If you aren't using your boat for a period of more than 14 days you must have a mooring for it. Very straightforward. That is until BW start adding restrictions over and above what the legislation sets out. That is the issue, that BW have coined the term continuous cruiser and defined what constitutes continuous cruising and then maintain that is what the Act requires. There is no doubt that if you follow BW's continuous cruising guidelines you would be complying with the legislation. To borrow the infamous lime green boat rule analogy, it is like the law saying you must have an area on the side of four feet by two feet painted lime green and BW issuing guidelines saying that you should paint your entire boat lime green. Clearly doing that would comply with the legislation, but painting your entire boat is not what the legislation requires. The issue is that you could also be complying with the legislation but not complying with BW's guidelines. BW are saying "this is what we say you must do to comply with the legislation" when in fact theirs is but one view of how to comply with the legislation.
For example, someone with a boat in say, Braunston was to set off for London, sets off every morning at 9am, travels until 5pm and moors for the night, then upon reaching London, stops for a couple for days before he turns around and heads back for Braunston, and then continues to repeat this trip. I would contend that he is within what is required by the legislation, namely that he is using his boat bona fide for navigation without stopping for more than 14 days in any one place. However he would not meet BW's requirements for continuous cruisers. On the other hand, someone who moors up to the towpath for a fortnight, before firing up his engine, travelling for a day, and mooring up again for another two weeks, but who moves on in the same direction without retracing his route would constitute a continuous cruiser. Yet it could easily be argued that someone who only travels the bare minimum to satisfy BW's guidelines is less involved, "bona fide", in navigation than the person in the first example.