Brown Sandwich Loaf Recipe .. at last

This is my first time posting a recipe of mine so please be gentle :)  I've been working on a brown loaf for a while that has flavour but does not take too much time to make.  After trial, error and a notebook I've finally come up with a happy medium.  I keep this loaf wrapped in a cotton tea towel in the bread bin happily for 3 days for sandwiches.  Reduce the butter to 30-35g if you only need it to last 2 days.

Preferment (12 hours + ish)

115g dark rye flour (Doves Wholemeal)
60g stout (Lancaster Black)
55g water - warmed
pinch of instant yeast

* for a stronger stout flavour do 115g of all stout *  I preferred this but hubs didn't.

The preferment does not go liquid and bubble but does change to a mousse like texture as shown below:

Final Dough

All of the Preferment
210g strong brown bread flour (Carr's 15% protein)
150g AP flour + extra 25g if needed (Allinson's Strong White 12% protein)
16g salt
16g active yeast
216g milk
40g butter
20g black strap molasses

Method

Mix preferment.

Activate the active yeast first with some warm milk and molasses.  Leave till frothy.

Mix dry.  Add wet and then form a dough.

Knead for 15 mins by hand.

Put in greased bowl and rise till doubled around 1 hour.

Knock back.

Form loaf and place in greased tin.

Rise once more until approx 1in above 2lb loaf tin.  Score top.

Bake at 170 fan for 15mins.  Turn.  5 mins.

Test and maybe remove from tin and put back for 3 more mins.