defurax, I cannot answer your question, but the reason that the Wednesday evening QF9 ex MEL did not depart DXB until 1102 on Thursday 22 October - as you suggest, almost two hours late - may have been due to a need for sufficient staff rest time ('slip') in DXB due to late running of a previous flight. This QF9 is shown as likely to arrive LHR at 1540, an hour and 50 minutes late.
The delayed Tuesday 20 October QF1 ended up arriving LHR at 2203 on Wednesday evening. This A388 turned around in an impressive one hour and 41 minutes to form a delayed QF2, departing at 2344 hours for the trip to DXB where its stay was from 0915 to 1150 today (overstaying by 50 minutes) so in consequence its SYD arrival on Friday 23 October 2015 is forecast to be at 0805, an hour and 55 minutes behind the schedule. Had this plane kept to the alloted time in DXB it could have shaved about 65 minutes off the total timetabled elapsed journey time from LHR to SYD, but this is not to be.
The delayed QF10 from Wednesday afternoon ex LHR (A388 VH-OQK) is due into MEL tonight (Thursday 22) at 2340, an hour and 45 minutes late, with the departure of QF9 back to DXB and LHR expected at 0130 on Friday morning (95 minutes late), meaning a probable DXB stop from 0820 (75 minutes behind time) to an as yet unadjusted departure time of a claimed 0910 on the QF website. The 50 minute stop shown there at present is unrealistic.
With the end of another month approaching, one has to feel a whiff of sympathy for the QF manager at the LHR 'station' (a name borrowed from railways) who may have to write another memo to the management of LHR explaining why QF's punctuality performance is not optimum.
Nonetheless it is good in one sense to have a profitable airline because it can then have the confidence to invest in new technology - something that may have been missing from say USA-domiciled airlines for many years until quite recently - but unfortunately this may not assuage many travellers who are merely concerned with travelling from point A to point B on time (with safety a 'given.')
QF's lack of punctuality on its MEL to LHR route through DXB would have to be one of the worst, if not the worst, performer of any airline offering Australia to UK flights. Of course other airlines require one to change aircraft in some cases at their intermediate stop (and one operator, BI even does a bit of a milk run from MEL to BWN then a stop in DXB prior to arrival at LHR) but SQ's timetabled Oz to LHR or reverse times can be faster than QF's, and yet SQ is more reliable in terms of not operating behind time nearly as often.
The QF SYD to LHR results such as this week's 16 hour departure delay and 15 hour arrival delay may be what statisticians refer to as an 'outlier' but those who were booked may not be all so forgiving. In QF's defence that was an afternoon when lightning had struck around SYD with one article on
Latest & Breaking News Melbourne, Victoria | The Age or
Australian Breaking News Headlines & World News Online | SMH.com.au showing a QF domestic flight approaching SYD with lightning bolts visible in the background - quite some distance away in reality but it looked 'close' in the photo or video.