Agree, not much videos etc inside the make room. Also agree, I think they somewhat randomly chop up fresh white cheddar (he says Sharp/Aged Cheddar in video).
Also, also, from the measuring Pyrex type jug of porter beer on make table, it looks like they manually add porter to the mix in the mold until they get the right consistency. This would mean that they don't separately combine presumably fine ground cheddar and porter to make the mortar, before adding to the chunks.
Lastly, I think they manually make each cheese with needing to ensure even distribution of large chunks and the mortar and to ensure that no voids.