Nobody has mentioned the use of vitamin c (ascorbic acid) to aid the rising process especially when using granary and wholemeal flour. Can be a little difficult to find the tablets- don't use the flavoured fizzy vitamin c tablet -although that could give an interesting flavour!! The local chemist orders in the tablets just for me!
A 500mg tablet is about right for a one and a half pound loaf and add it with all the ingredients at the beginning. Happy baking!