Just to add if you can borrow some trade plates you can just put them on the car and drive it, they are are taxed for any car they are on. Then get someone with fully comp insurance that includes driving other cars to drive it.
The owner can't drive it as 'driving other cars' only applies to cars owned by someone else. I once looked at temporary insurance but it was hideously expensive, cheaper to insure for a year and then cancel the policy They wanted £180 for 1 week against £250 for a year !