Just wondering if anyone has not bothered with adding electric hook ups and have used one of these instead?

Maypole 230V 13A Mobile Mains Power Unit with USB For Caravans, Camping, Campervans, Motorhomes : Amazon.co.uk: Automotive
Maypole 230V 13A Mobile Mains Power Unit with USB For Caravans, Camping, Campervans, Motorhomes : Amazon.co.uk: Automotive
amzn.to

