Some success this evening with Ollie & the new car.

We decided to put the back bench seat back in the car tonight limits his room but felt like Shona did maybe he had too much room.
Ollie has to stay in the house while we have the back gate open to get the seat out of the shed and into the car, so he can see us out there which gets him a little worried that we maybe going out without him, as we had already been out earlier he wouldn't want that.
It is now facing the hatch door with his quilt cover on it so he can sit on it and see out of the windows. I took him out to the car when we had done and within a few minutes he was in so I got on his seat too with him and we went round the block with his fan on as it was hot, and he seemed happy and not as stressed as last night and Monday night so we are hoping we have cracked it.
His head nearly touches the roof when he sits on the seat and he doesn't have any more room than in the Volvo but if he is happy and will get in and out with no problems like he used too I don't really mind. So fingers crossed he will be ok now, we are going to keep doing little bits the rest of this week and if he still seems ok Saturday we will take him somewhere nice and make sure we have time if he decides to play at silly beggars again so we don't have to rush him.
If this works I will buy him a harness. Have just brought him a soft dog crate today and pheromone spray and diffusers I thought if we sprayed in the car that might help too.
Thanks for all the suggestions putting them all together has helped.

Got my fingers XXXXXXXXXXXXXXXX sounds hopeful