This mixtape is full of rarities which are almost all identified. The majority of File a sounds like the sort of stuff that the Evening Show might have played and there are tiny little snippets of what sounds more like Kid Jensen than John Peel. The Screen 3 tracks are more than likely from their session recorded on 10thJanuary 1982, first broadcast 26th January 1982.  Nightdoctor, a reggae outfit from London, also did a Jensen Session at this time, recorded 11th December 1981 first broadcast 29th December 1981.  Both sessions must be repeats.
Then from the Killing Joke track at end of Tape A it turns more Peelesque. The Killing Joke and Higsons tracks are singles not the session versions that would have tied the show to 4th March 1982.
File b another change of style occurs with Emma Sharpe and The Features session identified as from the Kid Jensen show (first broadcast 10th March 1982)
Then back to Peel for the rest of File b is clearly from 10 March 1982 with the Skats session being the key identifier and at the end of the tape John Peel voice appears to say good night in a classic eeyore moment.
↑From Screen3 website : "Recorded Kid Jensen session. Went very well. Best ever studio sound. Produced by Dale Griffin, who used to drum for Mott The Hoople. Did 5 songs: ‘Come Into My Jungle’, ‘Family’, ‘Nuts And Berries’, ‘Fast Food And Discos’ and ‘Hearts In Limbo’." The last track is the only one unavailable on this recording.
↑Recorded 29/12/81 for David Jensen's show. Tracklist: High Fashion / Menelik / Jah Light / Too Late. Line up: George Young - drums / Roger Haires - bass / Charles Wood - guitar / Caroline Williams - keyboards / Robbie Coombes - vocals / Alan Deval - tenor sax / Freddie Cruickshank - guitar / Annie Whitehead - trombone / Terry Allen - percussion / Noel Job - vocals, percussion."