The history of LCY stems from the Dash 7, which because it could fly a 7.5 deg approach, this angle was chosen for noise abatement reasons. Actually a political rather than practical choice.
In consultation with the local authority and residents, the 146 operation should have been limited to 6 deg for noise and obstacle clearance reasons.
5.5 evolved as a better choice for aircraft handling. The obstacle problems on 10 were solved with a ‘cat2’ quality glide slope – enables reduce obstacle clearances, and there was some 'help' with building regulations. Hence the need for precision approach guidance, ILS or PAPI.
Touchdown scatter is (or should be) a by-product of a steep approach and the reduced threshold crossing height.
The original Dash 7 runway was ‘shortened’ (within the existing length) to limit operations to a level two airfield (jet) which had obstacle clearance and runway width / safety zone advantages.
The original ‘fixed distance markings’ were used to mark the optimum (last point of touchdown) zone. The teaching on the 146 was as remoak # 123 indicates. However, after a landing incident, it was recommended that additional lighting at the side of the runway be installed so that the crew could better define the point, as a long touchdown reduces the safety margin. IIRC a touchdown at the lights would assure a stop even with a spoiler failure (40%), but the crew had to recognise this and use full brake.
Since then the runway has been extended (level two torn up?) and the purpose of the touch down lights been reconsidered (146 interpretation still applies) as of a wide range of aircraft types now uses the airport.