Flyboy

I don't think you have a genuine HIN/VIN no. as it's in the wrong format. It will be found in more than one place on the boat. Maybe the fitting out person put it on. The correct format is as follows :- Recreational Craft Directive compliant vessels – 16thJune 1998 onward Hull identification serial numbers should on all vessels built after 16th June 1998 appear in the international ISO format with fourteen characters. The prefix should be the country code followed by the MIC (Manufacturers code) – three letters. This is followed by the production model and serial number followed by the month of production and year of production or model year. This is set out in this example: GB –MPP1A01234F001 GB (country code) Great Britain – MPP (Manufacturers Code,name), 1A (Model)1234 (serial no.) F (month of build), 001 (year of manufacture). This hull identification number should always appear on the transom permanently moulded or etched into the hull and occasionally on a permanently affixed plate. This is in the majority of cases to the starboard side of the transom. A second plate is often affixed within the vessel in a location known only to the manufacturer and sometimes the police. Some steel/aluminium vessels (often narrowboats) have this identification number stamped into one of the surfaces within the engine room.

Transom

Doesn't the Chlorine in tap water do all you need to keep the water clean of nasties ?

Doesn't begin with E, have another go.

Slipper

Tightened

Grudge

Shattered

Looking at the Barrus wiring diagram, everything on the panel is powered up via the ignition switch. The only possible path for a permanent positive supply is via the alternator regulator and its warning light. Very unlikely I would say, but remotely possible.

Most modern flat screen TV's will give you a signal strength reading in % if you go into the menu. Easy way to optimise the signal.

A small log periodic aerial works well in most areas. I've got one and never failed to a signal yet. https://www.ebay.co.uk/itm/Stealth-MINI-DIGITAL-TV-AERIAL-LOG-PERIODIC-4g-LTE-Ready-Aerien-Antenne-Antenna/150848879726?hash=item

http://www.itv.com/news/anglia/2018-04-24/four-injured-in-boat-explosion-on-fenland-waterway/

Narrowboat engines don't work very hard and tend to run too cool and this can lead to bore glazing. Higher grade oils contain additives that work well at high temperatures in a modern car but are detrimental in a lightly worked engine. https://en.wikipedia.org/wiki/Diesel_engine_problems

The Barrus 30 only has a single thermostat which simplifies the issue. Find the big pipe that comes from the front of the cylinder head, the thermostat will be under a 2 bolted housing. You won't have to drain the whole system to remove it. Disconnect the large rubber hose, then the two bolts & remove the housing to expose the thermostat. Make sure when replacing it you get the right way round. If you have to fit a new one, you may have to drill a 2mm hole in the thermostat flange, this aids bleeding of air. Just compare with the old one. Barrus do this mod. but is not always present on replacements. If you have the manual it will show the thermostat position on page15 https://www.barrus.co.uk/divisions/marine/diesel/shire/downloads/shire-manuals/

Yes, that's correct. The system gives quicker calorifier heating as well as quicker engine warm up. The twin thermostat system is not fitted on the Shire 33 & 35 models. The OP has not stated which engine he has though. I am assuming he has the more common Shire 40 or 45 model.