They climb up the wheels to get in.
I've posted on this subject a number of times, having had the wiring loom eaten by the puckin' fests. £2,000 to put right, not covered by
insurance or warranty.
They are creatures of habit, following trails of urine and faeces.
The ultrasonic electronic devices keep them away, but the sound does not pass through van walls and bulkheads. So you'll need more than one, for a big van. One under the bonnet, one under the van...protected from damp.
Our van is parked on a remote hillside so I have one poking through a slightly opened window and always check that it's on the lee side,if rain is expected.
The local men pee around their tyres, because rats and mice don't like to cross it... Like the gipsies setting up camp... The men make a protective circle round the campsite, while the women put the tents up.
Mongooses too won't cross a wee barrier... So my neighbours pee round the hen coops..
A tip there for Robmac.
My van is 6.2 metres x 2.7 wide.. A circumference of nearly 18 metres. After a good night out ,I can pee round it in one visit.
You've got a lot to do ,Phil... But you have youth on your side.