I suspect that the logic of the situation is that microlights are specifically designed to be particularly simple in operation - for example it's not possible (within placarded seat and fuel limits) to take a microlight out of CG limits. Therefore, microlight hours don't count.
Who am I kidding, the CAA are analy retentive on the subject of microlight hours for any other licence, and always have been. The DR9 is a pretty little aeroplane, but arguably much less of an "aeroplane" than many microlights.
However, that's the way it is - look on G-INFO, if it says "Aeroplane" it counts. In this case, I tihnk it's probably because the stalling speed is a couple of knots too high for the microlight definition.
G
N.B. Although I've not flown it personally "Noddy" used to come into our farmstrip very regularly. Chatting to the pilot and watching him fly it, he clearly had enormous fun and it's a reasonably capable little machine - you could do far worse. But, watch out for the annual club fees at WW.
N.B.B. Whilst Beagle is technically correct, most of the industry still call it "Group A", so don't worry about it unduly.