Couple of thoughts:
my van is a t5 LWB had it for about 6 years. It had a new engine at about 20k miles (warranty), common t5 problem.
Been ok since. Mine is diesel euro 5, so it is slowly getting banned (or costly) in the different ULEZ type zones. You might want to consider whether euro 6 or petrol might solve some of those issues.
Also consider how it is registered – a shuttle might be excempt.
I have driven a Ford a few times, I think it drove better than a t5 (just to counter the – people always recommend their own van! ;) )
Friend had a quite new ford and its engine munched itself with a fixing cost of about £7k (he just sold it as was).
I guess that shows that they all have issues.
In a t5 LWB I could fit about 5 road bikes and by sticking a shelf across the bottom that allowed luggage to go in there too.
A rear rack would allow you to carry more, but obviously comes with security issues (and also generally you dont want to have race bikes on the outside going to an event).
The more serious racers (as has already been suggested) use the motorhomes – much better for multi-day events. But are slow and relatively in-efficient.
If getting a t5 consider headlights – because the standard halogen ones are supposed to be awful (and you might be doing more night driving??)