It's a requirement of the marina we're in - they insist in insurance
She has declared that there is an engine and also that it is non-working, which has been taken as having no engine. I don't get it either, it makes no sense.
It is regularly maintained with blackening, survey and BSC, etc - it's a well maintained boat that they only live on with no intention, or desire of cruising.
I think it's an old lister engine. Removing it completely presents it's own issues - balance, stability, prop shaft/stern gland, etc.
No, it's on the Grand Union. Where we're moored, a licence isn't required because we're not on the cut - we're on a private residential mooring marina.