The standard loaf in the breadmaker uses 500g flour, so I've been trying replacing some of that with beremeal.
This is all empirical. more than 100 grams of beremeal prevents the loaf from rising , with the standard amount (1 tbsp) of yeast. Increasing this to 1 1/2 tbsp doesn't help.
So the maximum beremeal I use is 75 grams /loaf and the rest (425g ) plain flour. The loaf rises but not as much as a 100% plain flour loaf. The loaf is also very very moist, and it doesn't have the nutty flavour they described at the Mill, which is there in the shortbread.
Im not sure what to try next - Ive got about 1kg of beremeal left.