Paul,
had a garage customer with exactly the same scenario. The new injector came with two new bolts from TPS, of slightly different lengths! Sods law says he got them in the wrong holes, giving a slight blow at the injector seat, only detected when he removed the injector for inspection. Ross-tech gave me an ecu re-set procedure for the new injector, worth giving them an e-mail. With the time difference you will have a reply by the morning,
HTH,
Peter