PB:
Don't know how other civilian authorities outside FAA handle this issue. But if by chance your aircraft is N reg then you can petition the FAA FSDO with jurisdiction for a TBO extension. Then do your homework, put st/gen on a lead the fleet plan, and have FAA grant extension.
FYI, you probably won't get any help from airbus on this. They'd be happier if 105 would go way like a Lama. They probably allowed the -48 as an alternate to be nice, but won't revise the approved docs in MM. Lear has no dog in this hunt.
Good Luck.
W1