Here is the page from the Midland's May 1856 working timetable giving an instruction about down and up lines for future reference for clear working. The only surprises here are Derby-Birmingham and up and Sheffield to Rotheram as up (though at that stage that was the way you travelled Midland to London).
What is perhaps most signficant about the document is that it does not mention London: the direction of Up is by diktat - because Mr Allport says so. He may, or may not, have had a reason for his diktat, but, as far as the Company's servants (and anyone else) were concerned, that didn't matter: the General Manager had spoken.
And that is - and for the safety and convenience of everyone, has to be - the case everwhere: Up is the direction that 'the boss' - management - specifies. (He may, or may not, have followed a rule such as 'up to London' when he did so, but just assuming that he did, and what it was, can have - in extremis - fatal results)
That's a great find. So Derby to Leicester (then to Rugby, ultimately to St Pancras) was Up and the line that was flipped over was Derby to Birmingham! Further evidence that there was no such policy as "up to Derby".
Yes, very interesting. Whether it was the 'West' (Derby to Birmaingham, and Hampton) or the 'Bristol and Birmingham' line which is the reverse of might be expected is a matter of debate - resolved by Mr. Allport's decision.
But something I wonder - what actually changed on 1 May 1856, when it came into effect?
And interesting to see the 'Little North Western' so described, officially, by its operator (built by the North Western Railway, it was worked by the Midland from 1852, but not absorbed by them until 1871).