You say:
"Never been loose on the Motorway yet so no experience at all, just thinking about it."
Very sensible post, and the answer is NEVER to exceed your experience. Towing a caravan on a Motorway is easy. But because of the high speeds of other traffic, slipstreams from trucks and coaches, sudden side winds when crossing bridges and other drivers kamikaze driving habits and attitudes towards caravanners, etc there ARE hazardous situations which all need to be 'experienced' in a controlled manner BEFORE you start thinking about overtaking.
It actually always amazes me that some people with caravans are trying to overtake at all. Some of them seem hell bent on 'arriving first'.
Well, Big Deal, but does anybody care? Your family will (or maybe won't if you kill them all) care if you spread them all over the Motorway wrecking the van, car, and holiday in the process.
WE work on the principle that "we arrive when we arrive".
Is that so difficult? I mean.....What's the rush?
OK, you might get held up here and there, but it's very rare, in our 22 years of towing caravans, that we've EVER been seriously delayed by other traffic. Sure, you'll get slow parts of the journey, but are they really such a big issue?
You can always ring the site and tell them that you are running a bit later than expected. They won't eat you!
If you allow plenty of time for your journey, and actually ALLOW for other traffic, then life becomes a lot less stressful.
Chill out. Enjoy the journey. It should be a means to getting to your site, or back home again. Not an ordeal.
Above all, take things VERY steady when you first venture on to the Motorway with your caravan. It's a learnign curve, like everything else. I'm sure you'll be fine.
Enjoy your Caravanning.