Well, PN, you're probably right. But I remember being told that the HRS was basically a Lightning MRG tied to the appropriate axis and working in a 'heading only' mode only - which it did very well!
Autoland was indeed a mystery to anyone on 35 in the late '70s. Didn't it require some sort of lead-in cable to be installed at the intended aerodromes of use? I did hear that the reliability of a non-redundant system at very low levels was considered somewhat risky.....