a claim is made against the driver, not the insurance company. The insurance company stands in your place and pays the money.
If a claim has been made, you should have been notified directly either by TP, his solicitor or PIAB. One woudl then expect your insurer to investigate the matter with you to cometo a decision on fault, unless it was quite clear that you were at fault.
Your insurer would consult with any witnesses, if they were identified and the gardai.
You say that the only claim you made was for car hire. did you repair your own car at your own expense? Did you put in a claim against other drivers policy? If not, why not, given that you feel you are in the right?
Could it be that there is Court proceedings outstanding and that as part of defence of driver you are claiming against, a Counter claim has been made? If that is the case, your solicitor should have informed you.
In a nutshell, if you do not know, then phone your insurer/broker and ask if a claim has been made and the current status of the claim.