Hi Brian
I would say someone is trying to lead you up the garden path!
Qualcast B1 colour is blue, the nearest match is actually Ford Mexico blue, most of Qualcast’s side wheel mowers were light blue even their first one the model C in 1923, however some of their models were green for example their model H in the mid 1930’s and the rarest of all is their model K from 1928 with only 2 to 3 examples ever surfaced, they look like a Lloyds Pennsylvania.
Hope this helps
Regards The Hall & Duck Trust