If you put one minute late into Ditra it will ignore it, from the ones I have used I think the minimum is 3. Thameslink Ditra systems are quite basic, especially the older ones so the list of stations that are recorded are quite small and are only local to the station so York and Wellingborough wouldn't be on there unless they are there just incase MML want to stop there. The one at Blackfriars and City are very basic in any case.
The Southern & South West Trains ponsy versions may have all the bells and whistles but Thameslink ones don't.
I have a recording of Phil at Victoria saying a service to Bognor is delayed by 02 (yes he said oh two) minutes. Although I think the system at the Victoria (and Charing Cross for that matter) is quite strange with the wording of 'special' announcements.
Also I noticed a few years ago that Phil's pronunciation of 'Southern service to' is different depending where you are - at Victoria and Charing Cross it is 'Southern (pause) service to', and there was a difference at Clapham Junction platforms 13 - 17 (oddly not 12 though) where he said 'Southern service (pause) to' - but this has now been changed to the standard (the one used everywhere except Victoria and Charing Cross) 'Southern service to' with no pauses.
Also when the Ditra system was installed at Luton, for the first couple of weeks every announcement started with the chimes - that was stopped for some reason and the haven't come back.
Whilst I agree that the one at City Thameslink is extremely basic (and it seems to be a very old version of the software as there are pauses between each part of the announcement), I wouldn't say the one at Blackfriars is as it was the only Ditra system owned by Thameslink that had both Phil's and Celia's voices. Although there does seem to be a major problem with the system on platform 5 there (announcements seem to echo in the actual tannoy system).
I find it interesting that certain companies have more 'advanced' versions of the system compared to others - I would have thought Ditra would bung the software on a disc (or several discs) with all the announcement recordings and just have one type to sell - including a web update for new files. But I must say that you do hear 'train approaching' announcements on Southern and SWT but not on the Thameslink part of FCC (you do on the GN part).
I find the Ditra system interesting because of how versatile it can be when needed (it seems to be by listening to it), but is it actually easy to operate as some of the stuff it can do does seem complicated?