gazzer:
TKBar: DONT put the squidgy stuff in your engine. You have a corroded injector ■■■■■■/seal. I would assume you have a 330D in there? Common fault on those engines. Hardest bit is getting the old one out. You should see the water coming out underneath the injector when the engine is hot.
In the good old days long gone by, I made a short slide hammer using a wheel stud which could with a little effort ( some days lots) screw into the sleeve and pull it out of the head whilst in place , but do drain the water before starting the job.
Dave.