If they charge at one with enough space, yes. If not, no.

From my albeit limited (only using the same few for mostly regular holiday trips to the same area) experience using motorway services, non-Tesla EV charging points seem to be regular length parking spaces.

Users may have better luck if they own a Tesla as their charging area isn't just a 'converted' parking space in the main car parking area, but a separate are which, from what I've seen, has more space behind them not used as the thoroughfare between rows of space, though not specifically to be able to take long vehicles towing.

Hopefully such specialist facilities will appear in the areas designated for cars with caravans and RVs, though they may have to wait their turn given non-towing vehicles will likely get priority for new charging points first, as the demand for them has likely gone up a lot quicker.

"I’d suspect that, for most occasions, it’d be an unhitch to charge."

And leave it in caravan corner of the services whilst you go off to charge the EV. Might want to take adequate security with you!

One advantage of towing is that you can put a spare battery in the caravan.

I know a very capable EV for towing. It runs on tracks and gets electricity from overhead wires - so no range anxiety. :o)

79p per kWh seems excessive….