Sorry to hear about your trouble. My brother once bought a Chevy SS Chevelle which blew up 2 hours later and never managed to get the money despite much pursuit.
You should find out as much as you can about WHO sold the car, whether the company had just changed its trading name etc.
You had a valid claim under the Sale of Goods Act to reject the product but have chosen to have it repaired. You are therefore entitled to the cost of repair and legal costs but transport costs in the meantime may be too remote to claim.
I suggest you keep invoices for all work and labour including the report from the Alfa dealer and hard evidence and then lodge a small claim in the county court (as it was) which is quite cheap. You should get a judgement in a few months and then you can try to get it enforced.
At that stage any information / dirt / financial stuff you have dredged up will allow bailiffs to seize assets. You would be amazed the info you can find on companies and sole traders in England.
If all this sounds a bit too much effort my wife has great results extorting money out of toerags with a couple of large goons......
Good luck, toerags abound.