It worked. :)
Recipe variants or notes:
Warrigal greens instead of spinach (blanched in boiling water and hand-squeezed to remove excess water)
Home-made ricotta, and nore of it than the other cheeses.
Home-grown herbs (including lemon thyme, oregano, flat-leaf parsley, and native pepper, as well as the listed mint)
6 layers of filo as I was wrapping it around itself
Blended in a Breville Wizz (it would have been the Kenwood blender but I broke it some time back - must get a new one!) rather than mashed. Produced the precise grainy texture I was looking for.