DJE
Well-known member
Please pass on my thanks to your learned friend.You're second statement is manifestly true, you're first "reasonable excuse" argument debatable. So I asked a lawyer. His sense is that you are most likely right, assuming you were only aboard with members of your own household.
According to the new regulations, "No person may, without reasonable excuse, stay overnight at any place other than the place where they are living". The regulations cite examples of what might constitute reasonable excuse, but these are explicitly non-exhaustive. Which means that only the courts can determine whether a particular excuse passes the reasonableness test and there is currently no case law. Nor do the new regulations explicitly address the question as to whether staying on a boat - which is not acting as a home - may be construed as part of the limitless outdoor exercise in which one is now entitled to engage.
With the additional assumptions that you have complied with all relevant bye-laws, local regulations, and colregs, that you observe the guidance on social distancing, keep your boat in good nick so as to avoid raising the risk for emergency crews, that the vessel in question is privately owned, and taking into consideration the rapidly changing and often subjective regulations, then his sense is that prosecution would be messy and unlikely.
Which in practice means it won't happen; you may receive a fine as the police aren't sure of the rules either, which it would naturally be best to just pay.