Replacement for Front (LH) XT Shifter

philkeeble

My wife's 2009 Hewitt Cheviot SE with a 3x9 XT build has a failed front (left hand) shifter. Identical replacements are no longer available. The series is M770 with a Deore 22/32/44 chainset and an XT top clamp (bottom swing) bottom pull front derailleur. She needs a light action short throw shifter as she has small hands and reduced wrist strength. She has no trouble with the current shifter, but struggles with the current Altus set-up on her trail bike.
Do all Shimano triples have the same ring spacing? Do all Shimano 3x shifters work with all Shimano 3x FDs irrespective f 9 or 10 speed cassette? Does anyone have a recommendation as to what is the best compatible replacement? Worst case is I replace both shifter and derailleur.

Thanks,
Phil