Hi Ilippu
I assume that the instruction about picking sides relates to the theme topic rather than solving the puzzle. Yes, agreed, requires UK specific GK - I had to Google once I had identified the person referred to in the instructions.
Yup I
Defn is 1st 2 words modified by removal of extra letter. Word play is an old 4- letter word for advice followed by 2-letter word for the writer, teversed.
5 clues have alternative answers which would fit together when entered in the grid. I guess the setter couldn't work out a way to show this in the PDF.