lol PP :-)
Meryl, sounds a bit daft, but if you put a blanket in the back and a toy with his scent on that might work (if you haven't already tried it). But also, try walking past the boot/ side door of the car when it's open a few times without actually getting the dog into the car so that he gets used to it again and doesn't associate being near the car with anything bad.
Do this for a few days (yes. you will get funny looks from the neighbours, but hey-ho) and talk in a soft voice to him constantly to reassure him.
Then try using a command such as 'up' each time you want him to go into the car - use one hand on the lead (relaxed length) and move the other hand into the area you want him to go, with a treat or small piece of cheese in it.
Don't go anywhere, just get him used to getting into the car again and being rewarded - do this several times over the following few days.
Then when (hopefully) he starts getting used to being in the car again, take him on a short trip to somewhere really fun for him, park, canal whatever he enjoys, and really, really praise him each time he gets into and out of the car.
It will take time, but have patience and don't worry about looking daft!
If he resolutely refuses to get into the car - get in yourself with him on a relaxed lead with a treat in your hand and speak softly to encourage him in - get him to make eye contact with you by holding the treat next to your nose, then moving it into the car with you.
I hope it works - if not, perhaps another AB'er might have some good ideas?
All the best