V50 Engine Turbo : ECM/BCM Fault Codes

[iainmd]

Our 2009 1.6D is showing a few fault codes scanned with VIDA:

BCM-0101 Communication between control units Communicational problems with ECM
ECM-6720 EGR control - Flow too high
ECM-3000 Camshaft position (CMP) sensor - Faulty signal
ECM-4477 EGR control - Flow too low
ECM-4490 EGR valve - Signal too high

The history:
The car ran with a lumpy idle and occasional power hesitation and displayed a code stating that the EGR was jammed. As a result I replaced the EGR valvle with a Haas par from Eurocarparts. I cleared the code, reset the EGR in VIDA and all seemed well for about a week. Following that the problems re-emerged coupled with "Anti-skid service required" message on the dash.
The anti-skid message appears and disappears randomly but mainly when its wet. The codes above reappear if cleared after some time.

I have also put the car on new suspension all round since these problems started as the service revealed 2 broken coil springs. At 9yrs old and hoping the car will last us another 2yrs I replaced all shocks, top mounts and raised the ride height using standard Sachs springs (heavy duty at the rear) instead of the DRIVe spec lowered springs. I have no idea of that's contributed to any of these errors but would hope not.

What next?
Well there's the question. Part of me wonders if I should write the Haas EGR valve off as a bad idea and replace with a genuine Volvo part. Pricey at £214.
I'm a little worried that it might not be the culprit and that I end up throwing good money after bad. Any thoughts?