Hi Roy, I agree with 90% of the points you brought in your post, there are 2 things that bother me. As he does hundreds of these a month I get a very competitive price usually around £90.You friend is fitting a new nozzle assembly, a new cap nut new pins and ball and seal kit and then run the injector on an Bosch 815 test bench witch will of cost over £120.000.00 witch will take over a hour. Then factor in the cost of the data from Bosch and the running costs, your friend is not making any money the fingers don’t add up and corners will be cut. With investment like this
http://www.youtube.com/watch?v=ubsUlW8XXOQ you need to make serious money.
Common rail injectors are very difficult to repair PROPERLY and should only be attempted by authorized repairers and not non genuine guys like Darwin diesels and David Braebrook (db diesels )as he has tested them on his Bosch 815 test bench and found them to fail on nearly all tests. I can’t comment with the lads at Darwin, other that I have fit injectors from them years ago with no problems and I have been to there workshop and they seem to prosper so they must be doing something right.
As for David (db diesels) his background is in the Diesel industry he reached a senior position at MI before he established his small company witch concentrates on supplying specialist test equipment and tooling to the diesel industry. David has never reconditioned any injectors he is a middle man that just uses his contacts to supply them, most of them have been tested on manufacturers test equipment. This is the point I’m making when I wrote corners will be cut, like you commented he has tested them on his Bosch 815 test bench and found them to fail on nearly all tests.

If you want an insight to the unique way we look at injectors register to Autoinform at http://www.autoinform.co.uk/ Best regards, Martin.