The Spy who loved me screened at the Odeon L Sq in London in
35mm four track mag , also before the feature a 70mm trailer
Of Close Encounters was shown as they had 3 projectors
It was no problem.
Also as Stephen points out some 70mm prints had mono tracks
I have read there was a 70mm print in...
In 1981 that would have been in 6-track Dolby Stereo, Logans Run in the UK was in full 6-track stereo including inner left and rights
Dolby Format 40 unlike Dolby stereo with baby boom Dolby format 42.
It does have a Dolby System Logo in the credits but the 70mm print in the UK was non Dolby...
I only know the Warner and ABC Shaftsbury Ave only used 35mm Dolby Stereo prints and l heard they used a mixture of UK and USA prints
because of a late finish.
This film did screen in the USA in Split Surrounds at Northpoint where they used an SA-5 Surround Unit with a Dolby CP100 as this was a test before Apocalypse Now came out, so Superman was the first 70mm to be shown in 70mm Dolby Format 43.
I did attend a 70mm screening at the Odeon L Square for a cast and crew screening and this was the only 70mm screening in London as
the print went back to the USA after.
I know Max Bell from Dolby was at the remote desk in the theatre but cannot remember if this was screened in Split Surrounds...