Read up on swinging your compasses. Armed with that knowledge, you should be able to work out deviation cards for them.
You probably have some ferrous material (as Wotname suggested) that is affecting one or both of them. Anything iron or steel will do that. Also, hifi speaker magnets, or other magnets. Paint
spray cans. Keep plastic stuff around compasses, nothing ferrous. You may have to re-arrange your stowage to relieve your magnets.
Do you have access to a hand-held compass you could borrow, to compare their bearings. Seems to me that at this point you don't really know if either of your bulkhead compasses is correct.....