I bought mine from JCB as well and drove it back to Glasgow.
Asked them just to take the protective sheets off and jet wash it. It doesn't make for an exciting handover but at least the paintwork will be okay

When I asked on here about my drive home, I was advised going the motorway was probably the worst thing for a brand new engine as I should really be varying the revs. So with that in mind I would slow right down in 3rd and accelerate up through the gears. Other drivers near me must have thought I was crazy

I think as long as the oil is up to temp and you and revving the nuts off it, it will be fine.
I never noticed a paint defect until I was all the way home so inspect the car very carefully!!