Passed over Greasby also. One of those heavy-duty long beasties (I know nothing about helicopters!) with a rotor at front and rear; very distinctive sound.
Heard it on the Woodchurch too, seen it fly over about 3-4 days ago coming from the Irish sea following the M53 towards Chester, can always tell a chinook it has a very distinctive sound. I wonder why its flying around the Wirral? I also saw a AH-64 fly over about 6-9 months ago.
I doubt it was a wooka (chinook, sounds like wooka wooka wooka)they are unbelievably loud, so loud in fact I bet the MOD retrict where they are aloud to fly because of noise polution, was it a RNLI sea king? they are also big and lound, just a bit more common in this part of the world.
It looks like the army where doing some sort of training just incase anything was to happen over in Liverpool, they would use the Wirral to land supplies