Well, so far so good. Easy local loop (Crooksbury Hill/Tilford/Hankley/back home) just to ease the bike (and me) back in.
Enough rattly descents to shake down the rear end a bit, and nothing budged.
Beer and tinker a bit this afternoon. Need to re-adjust my rear mech properly (did it in a rush last night), as it's all moved a bit due to the different dropouts.
MikeT, up to a few months back, had no issues at all, P7 seemed bombproof. I would have recommended it to anyone.
Then all of a sudden, the non-drive side bolts seemed to just lose the ability to stay done up, even though they were threadlocked and not overtightened. Then all it took was a few grumpy ham-fisted trail-side adjustments with a multitool to kill them off!
Think I'll hold off the extra bolt for now and see how I go. From the pics of new P7s, looks like they have this as standard, so guess new frames may not suffer so much from this.