Dunzilla, close to 60 of 64 ever built aircraft are in Europe and spares are there as well. Sometimes you can see part numbers available somewhere else including Far East and Australia, but usually they are in "removed as serviceabe" condition without suitable paperwork. Unless BAE has positioned part of their stock to different location, I don't see who & where have lots of ATP parts there.
Didn't claim to be 'lots' but there is a considerable parts around the Asian region to be sufficient in providing stock to an Indonesian carrier.
As far as I know, BAe hold very little in terms of parts, whereas Westair own majority.