I've never read the original Christopher Marlowe play, but it's clear that Jarman cut up bits of it to accentuate the unreasoning hate for Edward II's lover Piers Gaveston.
Ha, no, that's pretty much textual, believe me. (I lived and breathed the play, film, and Marlowe's sources for my honors thesis in undergrad.)

it's not hard at all to put oneself back into the mentality of the time period
Och I feel so old ow.

Swinton is pretty much divine.