Not completing the hardest race I have ever attempted

Four years ago I completed the Grand Raid Pyrenees 80km in 20 hrs 39 minutes. It was tough but I was always well inside every checkpoint cut-off time. I didn't even think about cut-off times.
This year was different. I had recce'd the finishing 8k and found it much more to my liking than the 2014 route. The route to Pic du Midi was also different, going via La Mongie instead of Artigues. The 16km to the first checkpoint at Merlans Restaurant was no problem. My target was three hours to arrive there at 8am. The first 2km is quite flat so I just ran along with the rest at about 10 minutes per mile pace. Then the climb begins. The next 14km has 1500m (5000ft) of climb : you mostly walk it. I arrived at the checkpoint in just inside three hours. However, I did have to stop for a couple of short pauses on the final climb to Col de Portet but it was no cause for concern as I was holding my position. The next couple of miles were fine, just go with the flow, 13 miles or a quarter of the race completed in about 4 hrs 22. By 12 miles in, we were at a height of around 7,500 ft above sea level, heading for four climbs to take you over cols at above 8000ft. I was struggling to breathe on these climbs. I had to stop to recover for a minute or two. The stops became more frequent and longer. I was gradually being overtaken by most of the 200 or so who were behind me. I am well known for my lack of descending prowess and much of the flat parts had their difficulties being over boulder fields. I reached the final col at Pas de la Crabe. I had already decided much earlier that I would retire either at La Mongie or, try my luck at climbing and descending Pic du Midi which I enjoyed last time, then retiring at Tornaboup which is 51km (33 miles). At Pas de la Crabe I  knew I would not make the 1.45pm cut-off at La Mongie. One of the few other British runners, Bob Nash, overtook me whilst I recovered at Pas de la Crabe. He went way from me on the tricky descent before I caught him at the ski station. We then ran together, often with a French guy, to make the checkpoint at 2.30. Even if that had been the cut-off time, there is no why I would have continued. Eventually the few runners still behind us arrived and at 4pm a coach took us back on a 90 minute mystery tour to Vieille Aure.
The race was won in 10 hrs 54. The 2014 race was won in 9 hrs 33. In 2014, I reached the checkpoint at Artigues at noon : this year at La Mongie it was 2.30pm. Bob was one of only three V70s in the race but none completed. Of the 1163 starters, 147 retired at La Mongie, with another 90 retiring after. I know I am not as fit as in 2014 but not by a massive amount. The officials at La Mongie concurred that it was hard this year. Albert completed the 160km version but many hours down on what he targeted. Bob Nash's wife Karen also completed the 160km some 4 to 5 hours down on what she expected - yet she still finished 3rd woman.
It didn't seem to take a lot out of me for nine and a half hours and 8000ft of climb - just a shame I couldn't have put the effort in to reach the CP in say 8 hours.
I will post some photos of the area when I find suitable.