High level lights

you ask what are the disadvantages. more chance of water ingress for one.

you could ask, what are the advantages. I would say non. HGV's don't have them so why would you.

Why butcher the bodywork on your caravan and possibly devalue it? Goodness knows there are enough routes for water to ingress without adding to them. 

You already have high level marker lights and I think anything further would be pointless. 

Just ensure the ones you do have work properly on both the van and the tow vehicle, and use them properly!

Some road vehicles are lit up like Christmas trees, yet are actually rather ineffective as the drivers leave others guessing as to what they are doing, or which way they are turning. 

You must be wearing blinkers, i would say there are as many if not more C'vans on the road today with both high level brake lights and high level marker lights which are fitted when the c'van is built.

Well, that’s a nice friendly and constructive set of responses. Plenty to think about there!

Both our budget Abbey bought new in 2005 and our much more expensive U2 Bailey bought in 2014 had high level brake lights.

Well, you did ask 😗