Your post is a bit erm, confusing ....in part at least.
In the RAF, spares listings are contained in the Topic 3.... formerly known as the Vol. 3 to many on here. Every operator of an aircraft type would have the relevant sets of AP's therefore.
MU's were a bit different in this respect in that, due to their nature, they did have much more detailed information supplied by manufacturers when required for specific tasks, notably mod.programmes and repair schemes.
Depending on the era. paper and / or microfiche formats
The civilian version in the M.M's is the IPC.
At a guess, I would say the scanned document you provided was a purely Westland internal item until required by an operator for whatever reason.
Hope this helps ?