I believe the uk clocks should work as is and no need to program since they are a module in themselves, but if the van is lhd or continental then you may have to change the bcm config to mph somewhere.
Not having actually done this I'm hypothesising but if the clocks take their readings from the can bus and from the bcm then i believe the signal comes from the bcm and should in theory need to be told it is mph.
This may also mean that if this is correct then you may want to try it on your clocks to see if the needle points accurately to the mph marks in stead of the kph marks.
But i don't really know

I have an update available for my clocks but it just won't install it, you should use the same clocks you have which i lessons are the ones with the red band in the Rev counter, that is if you plan on changing them.
If you have the low spec ones then it is easier to replace them like for like, you can install the high spec ones but you need to also change the indicator stalk because yours won't have the trip functions etc.
56 350 2.2 130ps mk7 with 2 side doors
65 290 2.2 125ps custom with 2 side doors
07 350 170ps
Ids v86 licence + v86.04 update + xprog
hereIds map
here