Paul C

How are they "questionable" though? Is it only because you don't know the underlying legislation which allows them to do so? In any case, CRT have stated they believe they have the powers to do it, but its been untested in court. The relevant law (I've reworded slightly so it reads better - check out the original text here though: https://www.legislation.gov.uk/ukpga/Eliz2/10-11/46/section/43) is: "Canal & River Trust shall have power to ....... make the use of their services and facilities subject to such terms and conditions, as they think fit." I think CRT are as unwilling as any boater (so far) to actually go to court and "test" them.

Duct tape would probably suffice as temporary

Looking more broadly, it does illustrate how the advice of "buy a secondhand boat and get some experience before spending £xxx,xxx on a new build yourself" is sage. A £30-40k narrowboat is likely to be in reasonable shape, gets you on the cut, and would probably resell for similar with not too much bother. And it would be an investment in skills to learn how it all works, how it fits together, why some things are done the way they are, etc, etc. Look at it another way, a new boat is likely to take 2+ years from now to be truly "ready". Thats a long time in your adult lifehood to be waiting for something.

Which law are they breaking by the existence of short term mooring signs?

No worries, you're free to express your opinion. I am glad others (and OP) actually got my dry sense of humour.

Can you sell your boat and buy the other which is one digit out?

Because earlier,

The question wasn't for you

Driving licence or voter ID card would be okay as proof of ID. You have one of those, right?

Camera battery chargers.

You can get a tool which cuts down a normal sized SIM to a nanoSIM size: BUT you don't need to (and it probably wouldn't work anyway - not electrically, but because the old SIM isn't 4G capable). You can simply ask your network provider to send you a new, 3-in-1 SIM which you can snap off the excess to make it into a nanoSIM, and it will be 4G capable (because pretty much every network is now 4G capable).

Here's an analogy, hopefully for the hard of understanding: I go into a service station and want to buy a small carton (500ml) of milk. WHSmiths and M&S Food both sell milk, but WHSmiths only have 2 litre bottles. They are both able to sell milk, and neither is obligated to sell me 500ml. I can't make WHSmiths sell me 500ml of milk and if I ask if they can open a 2 litre bottle and decant some into my cornflakes at the 500ml price, they'll say no (but will happily sell 2 litres, at its price). M&S aren't obligated to sell me milk either, but they will sell a 500ml carton to me - because they have decided to offer 500ml cartons.

Yes. Regarding the whole thing, there is a danger of "overthinking" it, especially if you have no experience to relate to. I'd advise try a standard layout and a reverse layout boat for at least a week each, then you have something tangible to base a decision on rather than theory. We tried 5 boats (hiring) before deciding to buy our own.

Huh - the fresh water isn't at the front? On a previous boat it had a high-ish front deck and a rectangular plastic tank underneath it - installed from the interior. It left an awkwardly shaped storage area at the bow which was useful for junk that never came out much. On the current boat, the bow is the water tank.

Its not that they can say "no, we think you should be paying xx% split", its that a boat yard - indeed ANY retailer - is not obligated to sell anything, to anyone. Its not a public service they have to offer. So long as they're not discriminating against protected characteristics (eg they are refusing to sell to disabled people) they can choose not to sell to a boater who wants 100% domestic. They could choose to only sell at 60/40.