You should be able to refund the insurance company up until the end of the insurance period... which might allow you to see how claiming would affect you premium, and to choose based on that. You might want to check this with the insurance.
If the other party is agreeable you may be able to have his car fixed cheaper than the insurance company, in which case you may prefer to pay yourself.
I would have thought that you are better off claiming, it should cost less that way. Your insurance might be 600 Euro say, which includes a 40% discount (total guesses)... which would mean your full premium would be 1,000... so it'd only cost an extra 400 in year 1, and after a year or two you'll have built up a no-claims again...
I'd have thought it's only worth re-imbursing the insurance company for claims of 1,000 or so.