well first of all I wouldnt buy a 60ft pole just for their van unless you really need to. surely you can juggle one big pole between vehicles?
I would go with 2 x clx 22
and one medium sized pole poss clx 27 if you feel it will cover most of the high stuff, only you know really. or if you need a little bigger look at a slx 30 or 35
saying that its only £34 difference between the slx 35 and the supermax 40, but i dont have any experiance of the smax.