You might want to ask this question over at the Harbeth User Group. I am not sure you will find many Harbeth users here. Often on HUG, Alan Shaw will respond to questions directly. Of course he thinks that any good amp of 100wpc will work with any of his speakers but the members use many different amplifiers. You may find someone who uses Manley's with the 40.1.
Good Luck! I am a Harbeth (SHL5+) user myself.
Good Luck! I am a Harbeth (SHL5+) user myself.