Hello Angie.
Please forgive me if i'm wrong, but I sense you expect your husband with the HGV licence will be the one who does most of the towing. I would expect his professional skill will prove quite useful in coping with a caravan, but having said that we have had other professional drivers still seeking advice about towing caravans.
Moving forward isn't usually the issue but reversing a caravan can seem quite alien at first , even for articulated HGV licence holders. The main difference is how quickly a caravan will start to turn with minimal steering input when reversing. Its down to the shorter distance from the coupling to the caravans road, and the difference in the field of view the rear view mirrors provide compared to an HGV.
Don't be too blinkered about which caravans you look at, in particular the differences between single axle (SA) and Twin Axles(TA) caravans are not as important as you suggest. In particular there is no evidence to suggest a puncture on a TA caravan is any less serious than on a SA caravan. In fact a puncture one one wheel of a TA can often lead to early failure of the second wheel on the same side with twice the inconvenience and cost. The best strategy is to have tyre pressure sensors fitted that will warn the driver if a tyre is starting to lose pressure, before it becomes a total failure.
I appreciate Raywood's response was well intentioned and he make some valid points but sadly there are a few factual errors in his posting.
Raywood implies all TA's are heavy caravans. That is not strictly true there are several examples of lighter caravans with TA's and some of the largest caravans available only have a single axle. The difference is the caravan manufacture has chosen to fit a second axle, not to cover any technical weakness but more of a status statement.
He suggests that you can't tow a TA caravan on just a CAT B licence. That is not true, the post 1997 driving licence CAT B entitlement limit is a combined MAM not exceeding 3500KG and makes no reference to the number of axles on a trailer. It doesn't matter how many axles a trailer has as long as the combined MAM of the outfit is no greater than 3500KG.
Mealsonwheels has referred to the caravan industries advice about the 85% towing ratio. This is just advice it is a sensible starting suggestion, but its only part of the solution to getting a good safe tow. Importantly the 85% has no legal force and it is most certainly not a "Rule" only advice. Other factors are sensible distribution of loading, car and caravan in good mechanical condition,correct tyre pressures for towing, driver awareness of road and traffic conditions.
If you go for a larger caravan and especially if it does have twin axles, the addition of a caravan mover will be a boon when it comes to final positioning on site or in storage, Especially if you have to manhandle the caravan. TA's are notoriously difficult to turn by hand in small spaces. However if there is space to use the tow vehicle a good artic HGV driver would probably mange very well without a mover.