Good point. Some of those who left in the following days may have contacted the UK police to give statements or information. Prior to the review, I wonder if the UK police could have contacted any who hadn't spontaneously contacted them without a formal ILoR.
I think it's perfectly possible that other holidaymakers at the OC complex have been in contact with SY - either by their own volition - or after an approach by SY.
IMO it's a big mistake to assume that the only witnesses there are in this case are only those people who gave the statements which are in the files.
For instance - there could be loads of people who saw Madeleine at different times on May 3rd - but who would not think it was necessary for them to come forward with that information at the time - as no doubts were being expressed about her whereabouts on that day - especially as they had been confirmed by the nanny,Charlotte Pennington(?).
I can also understand that having established that CP was not known to the McCanns (and so they had no reason to disbelieve her statement) that the PJ would also think it was unnecessary to find other 'independent' witnesses to confirm how Madeleine spent 3rd May.
For instance, imo this has led to the discussions querying whether Madeleine disappeared before the 3rd - by assuming that CP was the only witness to that - and by throwing doubt on her veracity.
IMO many more witnesses have been interviewed by SY than we know about and whose evidence may well have assisted them in ruling out the McCanns and their friends as suspects or even persons of interest in this case.
It's a grave error IMO to assume that SY only have the same witness statements that we are privy to - i.e. the ones in the files.