The episode with the truncated version, positioned at the end of the episode just before the end credits, was included in the episode first broadcast on 13th November 2016 at 8pm on Channel 4. I am struggling to find the other episode but this should give you a head start.
I think I must have dreamt the ‘other’ reading - I can ‘see’ Tim West sitting on a canal bank reading the whole of the poem, but the production company can’t trace it.