Hi Steve
really sorry to hear about the smash, hope you're both recovering well. I would have a look to see if there is any CCTV on the junction and then make a request for the footage under the Freedom of Information act. You will not be able to apply for footage of the other vehicle, just yours. However, the footage of your car should show the state of the lights at the time.
It's a long shot, but the police would subpoena this information as part of more serious investigations
Hope this helps
Minty