Chevron
thinking about it a bit I seem to remember there was a more accurate aid than SRA -Precsion something radar?, where the controller gave a running commentary of turn right 3 degrees , just below the glide etc . all very small corrections. (of course I can remember that from 196X but not what i had for breakfast today )
ATC also asked aircraft to report crossing the Thames which I think was at Laleham nr Staines -no outer marker on that runway and also reminded the crew to check wheels down and locked . At some point nearer the runway they just announced cleared to land approach completed and I assume left it to the crew to decide to land or not at decision height
The other thing about 05 R was that the approach passed over a massive fuel farm at about 100-150 ft so any undershot was going to end in a mega catastrophe.