Ford won't do any work on the metering heads and there's only a handfull of Bosch-Service-Stations in Germany who dare to open them...
According to Bosch there's no way to repair them just send them in and get a nearly new one back. But this costs as much as a new one...

If you dare to open it yourself, you'll get all gaskets and other parts at a Bosch-Service-Station...

But it's better if you've got two ore more metering heads to open, because most of the people won't be able to put it together again