enigmatic

does sound a lot like drive plate. my engine mounts only rattled at low revs (but were pretty bad in neutral too). I guess there are some bolts etc that might need a specific RPM range and load to rattle. I guess the people who know more about gearboxes than me might want to know the model of gearbox (or more generally whether it's hydraulic or mechanical) to make any suggestions on that front

FWIW the trick that seems to work involves waggling the pedestrian gates before turning the key and trying to shut them. If they are not in precisely the right open position they don't unlock and so can't be shut. took me and the boat behind 15 minutes of trying and failing and not getting any help from any of the official numbers before asking at the adjacent boatyard locals crossing told us with some amusement that it had only been "fixed" the day before

I've seen a few in fields. I believe they fertilise the soil so that new narrowboats may be grown

There are moorings the other side of the rail bridge, but not really more cat friendly. Cat will probably enjoy it more when you've moved down the Trent. Loads of space on the fields above the pontoon at Torksey, and most of the non-tidal Trent moorings are rural... Amazon deliveries to lockers are usually good, am sure they do phones too