Hi Dave, I have certainly met some awfuly aggressive mongrels here. From generation to generation the components of the buckfast will alter and this can leand to extremes. Especially where they are in an area where 95% of the other bees are carnica. In our "county" there are 1200 colonies, and most of the beeleepers breed their queens on site - unfortunatley not making use of the isolated queen mating site nearby.
That being said, I have some colonies of Carnica (lovely looking queen) bees with orange - red rings that are very nice to work with.
br
Calum