Thanks ... that works for some of the problems at least! ... but boy that's an obscurely hidden way of fixing a problem, when surely we should just be able to edit the "no style" setting the way we can edit all the other settings!
Even after switching the text box and artistic text "defaults" handwriting is however still somehow the Affinity programmes' default font ... and I've absolutely no idea why that would be the case ... if I open a document with missing fonts, I have to switch all of the fonts to something sensible before I'm able to read it ... why isn't there something simple in the preferences to set a default!? ... most other programmes with a default go for something that's at least legible!