Horse Box lorry - advise please

FOG being a 4x4 forum, I have noticed there are members that do have horses so I'm hoping that perhaps some of you guys can offer a bit of advise/pointers on what to look out for when buying a 7.5 tonne horse box.
Where I'm coming from is that my daughter wants to push on with getting a horse box so that she can start entering my grand-daughter into show jumping competitions. Me doing the dad bit, don't want daughter to jump in and find out there's alot of stuff she should have taken into consideration before buying.
Grand-daughter is in a fortunate position of having a big old lump of a horse that she can use - basically this horse was bought for the daughters of a family for show jumping, but they have lost interest and the owner doesn't want to get rid of the horse. That's where Chloe (my grand-daughter) came in, the owner asked my daughter if Chloe could exercise her horses on a regular basis for her. Chloe is quite a competent rider and capable when making horses jump over the fences, so this is to good an opportunity to miss. The only missing bit of the jig-saw is getting required horse transporter.
7.5 tonne horse box ticks the boxes because of the basic human dosing facilities that can be found within these vehicles. Son-in-law as a heavy goods vehicle so he's drawn the short straw for doing the driving, then it's me with the grand-dad license.
Horse trailers have come under the radar, but it would mean them having to buy a capable 4x4 to tow it plus they wouldn't get the dosing facilities when they are away at these shows. Seems the lighter van size vehicles don't have the carrying capacity or live in facilities.
They have got a friend with a yard that they can store the 7.5 box when not in use.
Any pointers will be very much appreciated.

I would say the normal rust/rot body,cab and chassis. Servicing etc

Check floor,as sometimes the floor isnt washed down so urine etc rots the floor away,from what i understand horse lorries are exempt from tacho as its private use,also the 6 weekly pmi check that all vans and lorries must have done if the van/lorry covers more than a certain milage each week,but again horse lorries are exempt from this,but for peace of mind might be worth getting the seller to do 1 and this will highlight any faults etc,tyres will not be cheap,and get breakdown cover just incase as recovering a 7.5t will come under as commercial and will not be cheap.

As a complete aside if you do ever break down i have access to a horse trailer so can assist if need be.

Here ya go Pete, a good read of this may be of help

Allthough a 7.5 ton horsebox can be driven on some car licenses depending when it was obtained the said lorry has to be plated by vosa. My old boss used to have one and he gave me the task of taking it every year. The plate should be on the passenger side just by the seat. Hope this is of help?

Thanks guys for advise, all very valuable.
Will deffo look out for the VOSA plate Bobby, many thanks for that.

Pete if it's any help at all I know nothing about horses,horse boxes or 7.5 ton trucks :lol:

So I get the nice clean Job