Well I finally got them all out with No 2 being the PIG. I had to break the bridge clamp holding 1 & 2 to release 1 and give more room to work. Tap a chisel down the sides between the forks and the injector body and the brittle forks break off. Still couldn't extract No2. so decided to sacrifice the cyl. head cover (£60) to get more extraction options. Didn't use the angle grinder to cut the cover as it would spew far too much plastic over the camshafts. I used a soldering iron with plastic cutting knife bit to create a hole about 50mm around the stuck injector, then lifted the cover over it.
More huff & puff and before trying the stillsons, I made the slide hammer heavier and took more care to align the impact shock central to the injector. Also removed trhe HP union and used that to hold my slide hammer fixture solid to the injector body. Each slide hammer blow raised the injector about 5mm until it was clear. Checkout the Laser tools injector remover if you want to copy theirs.
Visual condition: Injector 1 oily but clean, O ring still in the groove. Injector 2, Hardly any oiling up, good O ring. Injector 3 oiled up and O ring fragmented. Injector 4 a total mess. with lots of black gunk and hard bits of carbon/O ring outside the injector body, O ring seal gone and groove filled with gunk. The OE seals are 16.2mm ID x 1.5mm. I think they were Buna-N. I shall replace them with 16mm x 1.5mm Viton rings and replace each injector with injector grease.
Parts lists shows O rings at the end of each nozzle and some sell kits with 2 O rings per injector. If there's an O ring on the nozzle, It must be way down at the bottom of the cyl. head and I haven't explored how to get to it yet.
Off to the diesel injector man tomorrow to have them all tested.
Everybody tells me these CR engine injectors aren't serviceable? Not sure what they mean because the black electrical connector body can be removed by the large 29mm nut - watch for the small spring, washer and bypass jet pintle! After that everything is mechanical. It looks as though the lower half of the injector body can be separated? I suspect they can be disassembled but you can't get Bosch small parts and more important, measure and qualify the flow calibration.
Onwards & Upwards!