We visited the Barony Mill when in Orkney in June, and came away with some Beremeal and the recipe book, which Ive been using (slowly) since. Orkney Bere Bannocks have been OK, as has shortbread , made with a proportion (3oz meal + 5 oz plain flour) of the beremeal, but getting it to work with in bread,made with the breadmaker has been much more troublesome.
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.