As mentioned previously, when walking along the Lee Navigation I couldn't help but notice a protest was being arranged later that day by the narrowboat community. They were concerned about a potential reduction in the numbers of moorings, as described in this article.
So a thinning of the boats would bring benefits. It would also help other water users, such as rowers, kayakers and canoers.
Maybe additional narrowboat marinas are needed, such as this one on the right of this photo:
Maybe one of the large unused docks could be transformed - such as the Royal Victoria or Royal Albert Docks where the Lea meets the Thames?