Quite a few (all?) modern Thrust Management Systems now include a slight increase in idle power with some / landing flap extended to "prime" the engines for this eventuality by reducing spool up time.
If inclement weather was around, it was pretty gusty at MAN on Wednesday, then it is possible that there was windsheer. This is a sudden change in wind speed and or direction. The result is often a sudden drop or rise in airspeed which in the latter stages of an approach may cause a sudden increase or decrease in the rate of descent. This is particularly the case at MAN if the wind is either Northerly ish or slightly less so Southerly ish on runways 24 as the airflow is disrupted by the buildings to the north and trees and banking (probably where you were standing) to the south at low level. Yes, I know I have covered every angle but that is what makes windsheer unpleasant!
If we assume it was negative sheer, a loss in speed and an increase in RoD, then the response is a Go Around. Certainly the 757, 767 have a windsheer detection and indication which mandates a go around. I can't speak for Airbus. So, high RoD, time required to spool up, I guess I have given a long winded agreemet to the touch down in the Go Around theory as being the more likely scenario.
Good to see a sensible and genuine question rather than excitable speculation from the spotting fraternity.
