Manley with Harbeth Monitor 40.1

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. 

Sorry, haven't heard Manley but I just picked up a Rogue Stereo 100 and it sounds extremely nice on the 40.1's This is a very nice match. Heavenly, in fact.

I used a BAT preamp and Manley Snapper amps with the SHL5's and it was gorgeous.  Then went to the 40.1's and it never did sound good. Maybe the added power of the 250 amps will provide more control over the bigger Harbeths.