I'd like the same feature for the opposite reason: Searching for places to stay in our camper van often show great looking places that are for motorhomes only (ie, they have no on-site toilet/shower facilities).
I know I can filter results using the "Toilet block" check box, but I still feel like it would be easier for all involved just to separate motorhomes and camper vans.
To my mind, camper vans are _usually_ smaller and do not have their own toilet, whereas Motothomes tend to be larger and with their own facilities.

This is also an issue for booking. It is very easy to book a pitch thinking it is for a motorhome to then find that it is campervans only. The search for motorhome pitches needs to exclude these. Campervan searches can still show motorhome pitches but motorhome searches should not show campervan only pitches.

Yes, they do. Depends on the type of licence they are holding.
Mostly bc they differenciate between self contained bigger RV which are heavier, need EHU, fresh and grey water on hard standing and more natural and lightweight tent camping on nice grassy spots with sanitary facilities.
With campervans, landies etc we are a chimera: we need the loo and showers, like to live outside and feel more like tent campers (albeit with a metallic tent) than any motorhome.
I never feel comfy when I need to pitch next to a huge white RV and am very happy when I am allowed to park on the tent grass field.
So the probs start when the CV is not self contained.

Yes. The kind of sites we favour (smaller eco sites and farmers fields) are happy with smaller campers but don't like or cannot accommodate (due to access restrictions) larger motorhomes.

It's not clear whether campervans (e.g. a VW AutoSleeper) are classed as a motorhome or a tourer (which is what? A caravan?) or whether they are not allowed at all.