I'm not sure, but...
Having brought a US car into the UK, all I needed was a bill of sale and an MOT certificate to get it registered. I don't think you want to get too drawn into the whole more modern-day certificate of conformity thing.
I'd suggest you get an MOT done, get the car insured in the UK, get a bill of sale or proof of ownership and then send off for a registration to the DVLA.
But others may have better knowledge. What's for sure is that the government has closed all DVLA offices and so life has become harder than it used to be when it comes to registering cars. Nevertheless, you should be able to get some advice from...somewhere.