Freelander 1 Injector fuel pooling

I have recently change all four injectors and was sure everything was clean but I have found that fuel must be passing by the seals on the injectors,I fitted new seals and copper washers.I have read that you should reseat the injectors but I don't know if this has been done before ,how many times can it be done and can you buy over sized copper washers to make up the gap?The C clamps are tight and will the injector seal when the carbon builds up? I want to thank you all for the advice on this site I just changed the Turbo and the HP Pump
Andy