pj67coll, you do not mention in which cabin you were sitting and service expectation is directly related.
As to the landing at LHR, the field is well known for eddies of wind around the big buildings and an upset of the kind you experienced is not unknown and can indeed happen anywhere at any time. The reverse that I have experience is an approach where the aircraft is rather 'jittery' but when within a few seconds of touchdown - suddenly everything smooths out and all is gentle. That is the luck of the draw and has less to do with automatic landing equipment and/or the flight crew than may be imagined.