Buy the right vehicle for the job is what I do. My last camper was a caravelle and new one is a shuttle. All M1 class allowing me to do 70mph and based around a plg. I pay the extra for this very reason. To avoid all the hassle you get with buying an N1 van and hoping DVLA will let you change it.
There is a real good reason Cali's etc have a high price tag over a commercial van. Lets not go forgetting just because dvla change it to camper that allows you to do 70mph, its still N1 class so you cant. Yes you may get away with argueing the fact but honestly is it really worth it, a lot of stress if you have a busy life.
Clearly no good to those that have a van now but for those looking for the future, pay the little extra to get into a velle or shuttle if you find the speed etc will be a problem for you.
You do sooo much homework to buy a lovely van with the options from factory but not for everyday driving on the roads.
I totally agree there needs to be a huge shakeup with who says, what means and when does. VOSA, DVLA, Police, GOV tax the lot need to come up with an idea to ensure everything is inline and there is no wrong or right answer at this present time but I would personally recommend going for a M1 in the beginning to save the agro later. Its a sure fire way to get a fairly universal van.