Not had time to review the whole population but have reviewed the middle third of the men's results.
Runner 51150 - skipped the 25k mat - he ran over Tower Bridge very close to me but then finished nearly half an hour before me....
Runner 21921 - skipped multiple mats in the middle section of the course. Also doesn't look as old as the category he's running in.
Runner 35546 - missed the 25k and 30k mats - his second half was nearly an hour faster than the first half.
Runner 43227 - went straight from the 10k to the 40k mat; he's wearing quite a natty black jacket in all his pictures - which are all from the last 2k of the race.