m54 camshaft manual rotation

I fitted new vanos seals nearly 2 years ago, only thing is I think my camsensor had failed long before this and I only discovered failure late last year P0369 fault . I have cleaned solenoid pistons and replaced both sensors with oem parts and switched solenoids.
Since fitting new parts I have had various camsensor, solenoid and vanos faults. These have settled down to the regular P0369 and 18 on inpa.
I am thinking that my vanos pistons are seized with the "new" seals.
My question is if I remove rocker cover can I rotate cam shafts to get vanos pistons moving again or does movement only accur by the pistons rotating the cam shaft. Wondering if this will save me the bother of ripping the vanos unit again.
Related question where can I get a wiring diagram for the sensors specifically the exhaust.