Crank position sensor

[guy Willoughby]

My Insignia 1.6 cdti 2017 has had numerous sensor problems over the last 2 months, 1st was the oil pump solenoid and a po6dd code, also an esc service light. Changed the solenoid and both front abs sensors, problem solved for about 2 days, then I am getting service vehicle soon message, scanned and got the crank sensor code saying no correlation with cam sensor!! Starting to think the ecu is goosed? 

Anyway went to attempt to replace the crank position sensor and what a nightmare, you just can't do it without what looks like removing half the engine. Has anyone managed this or is it a big job.

[guy Willoughby]

Also if I unplug the solenoid valve sensor, the other problem with the crank sensor stops showing up?