Lympne/Ashford airport got a concrete runway because of I think 2 crashes in a day including a 748 that ended up on its roof.
I think it was a year later that it was all over for Lympne and its new concrete runway.
You are confusing two events.
G-ARMV crashed at Lympne 10 July 1965 when landing bad weather. the nose wheel dug into the grass and the aircraft overturned. All 52 occupants escaped.
A hard runway was built which came into use in 1968. Commercial operations ceased at Lympne (now Ashford) in 1974 although it kept going for light aircraft until 1984.
The famous 'double-'eader' was at Portsmouth on 15 August 1967. G-ATEK overran the runway at 11:48, followed at 13:34 by G-ATEH. Famously it was reported that the controller said he didn't tell the second about the first because he thought "it might put him off".
This caused the cessation of commercial ops at Portsmouth and lead ultimately to the closure of the airfield.