That looks cold but fun! And a decent mileage for this time of year, I hope you found some warm accommodation for the evenings.
I did the Reivers route as part of a round trip with the C2C, I particularly like the area around Keilder and have been back a couple of times. Those forest roads are a good argument for hub gears, they wrecked a chain, cassette and jockey wheels on the bike I used, and you could hear them grinding away.
Have you done the Lon Las Cymru route? It's very similar to the Reivers, I’d say if anything a little better, and a little hillier.
I've given up on Pitlocks, I had trouble with two sets. Now use the Trax security skewers (around £10 on Ebay) they're not as secure as Pitlocks, but with them on three bikes for three years I've never had a problem.