I liked it too 🙂 And congratulations on getting out and doing it rather than waiting for ideal conditions.
It’s certainly easy to “hit the wall” around the 60-70 mile mark when heading east. What earlier seemed like consistent good progress suddenly turns into a crawl over a never-ending series of steep climbs, with the clock spinning crazily while the mileage barely ticks over. Especially as there are quite a few cafe stops and you can convince yourself you’ve earned them all!
Last time I rode the SDW I started at Eastbourne, and the time-trap effect didn’t happen. Getting the worst of the climbing out of the way and ignoring all the tempting cafes, while still relatively fresh, made a big difference to the overall time.