Umm. I have had a bad experience in the past with a third party who was at fault and with the same insurer as me. Basically my insurer told me his policy details related to a policy that had lapsed.
I sought legal advice which was that since the policy had recently lapsed his previous insurer would normally be chased as "insurer responsible" and that they would be responsible for chasing him for the whole sum, if he could not provide valid insurance details. Sounded a bit odd to me, but that was the advice I got.
Guess what? My insurer (also his insurer, remember?) claimed they couldn't trace the bloke and I took a hit on my NCD as a result (protected, thankfully). I decided to phone the bloke up and asked if he'd mind reimbursing me for my excess, and got a cheque for the full amount by return of post. Really difficult to trace, eh?
I think insurers will fall over themselves to help if there's something in it for them, but if both parties are with the same insurer, well, call me cynical if you like... but the best they can do is to pocket both parties' excess and plead ignorance.
If you have legal cover included, give the advice line a call. There's no doubt in my mind that the third party is at fault. I just wonder if direct line are dragging their heels because they know they can't win?
Kevin