Brother in law recently bought a Mercedes AMG 63 for just over £40K.Back to the original question......
The real risk of your motorhome being stolen is reflected in the cost of the premium.
£400 a year for a £40000 vehicle is pretty cheap and reflects a low risk of a claim.
I suspect a £40000 prestige car would cost a bit more.
Even with mods, insurance premium was just over £850.
And it's a heck of a lot more fun to drive than our motorhome