In view of the attempt to muddy the waters, I thought it might be useful to the OP for me to summarise what I have said in reply to his original question:
First, there is no doubt that he would be in TECHNICAL breach of the law and this would be true whether he was wildcamping or on a camp site. It would also be true whichever way the front seats were facing, whether there was food on the table or whether or not the bed was made up.
However, there is very little risk of prosecution because of the need to prove INTENT. In the case of the driver prosecuted on his own drive, the engine was on and any passing police officer might think he had a reasonable chance of showing intent to drive. But in a motorhome, unless you are sitting in the driving seat with the keys in your hand, it is much more difficult to prove. I have referred previously to the advice given by my retired traffic cop friend (backed up by several other converstions with the police). And even if the police decide to take it further, it is unlikely that the CPS would follow through. But if they do, then it has to be proved in court and several lawyer friends have all agreed that this would be extremely difficult. My wife agrees (before retiring, she was a partner in a large firm of solicitors).
All of which is perhaps the reason why neither I nor anybody else I have spoken to can think of a single succesful prosecution. I have asked previously whether anybody here knows of such a prosecution and so far nobody has come forward.
In short, everything involves a risk and we all have to make up our own minds about whether that risk is worth taking. I usually open a bottle of vino tinto most nights, whether wilding or on a site, and have never had a hint of trouble from the police. If you choose not to, then fine but if you fancy a drink I wouldn't lose too much sleep about prosecution - unless you are one of those stroppy buggers who shout their "rights" at the police and thus give them the incentive to find something to charge you with (and they usually can find something if they want to!).
