That’s why I said it is what
insurance say that will decide but that is not the law. If you want to check it is contradictory but includes:
Although side facing seats, with or without seat belts, are not illegal, we would not advise that they are used. This is because seat belts are not designed to be used with such seats. In the event of an accident, seat belts on these side facing seats may help to prevent the wearer being thrown around the vehicle or from being ejected, but in a frontal crash they can increase injury risk by subjecting vulnerable parts of the body to higher loads than seat belts used on forward facing seats.
Driving campervans with passengers - GOV.UK[/QUOTE
I suggest you read the actual regs. The first paragraph on your link says
This document provides general guidance and advice on the legislative requirements in Great Britain relating to the carriage of people in campervans. Every effort has been made to ensure that it is factually correct but recipients should check with the producers of this document if they are unsure about the validity of a particular regulation after the date of publication or if they have reason to believe any part is not correct or is now out of date.
Have you ever known a government publish something that was wrong. Or contact them saying you believe it may possibly be wrong.
I read the regs like Trev did because it effected me.
What people choose to do is up to them and of no concern to me. The question is of the legality.