hopefully i can confirm some details for you...
firstly the session:
it was BBC session at Maida Vale studio.
1. we will rock you (slow), Brahma narration, we will rock you (fast)
2. spread your wings
3. it's late (into get down make love ending)
4. my melancholy blues
now the not so clear bit.....the "live bootleg" you have is in fact a "fairly clever for the time" doctoring of the original session. i say "clever" because at the time that tape originally surfaced (about 1987) the audience loops put on there woulda required some knowledge and trickery to achieve. listen to the quiet bits - the audience fits - even tho it's clearly a loop.
i had an early generation copy of this tape long before the internet and CD writers exisited for pcs...it was called "Queen live - Middlesex England 1978"
hope this helps
go deo na hÉireann