I've realigned the CCW mode and it is now locking reasonably.  The cavity had become misaligned and I had to adjust it to get it back on resonance.  I then swept the laser and maximised the peaks in transmission.  Next I put the PD back in for reflection locking.  I had to replace the mirror mounts with lens mounts because of the lack of room.  I adjusted the PD position to get maximum DC power, and then plugged it back into the PDH box.  We are getting dips that are approx 50% in voltage.  I couldn't get a decent error signal after the mixer until I reduced the sideband frequency (it's at 9MHz just now) but at the lower frequency we do get an error signal.  It's now locking reasonably but needs more work on the servo settings to get back to where we were before.