I got away from home just before 8:30, and decided to use the A12 cycle path to Kelvedon to save a little time. At Kelvedon, I didn't think it worth even checking the Railway, assuming the posse would be long gone (as they were).
I was going pretty well (10 miles from home and ~6 to go to), and on for arrival at the HA around 9:40 when I noticed something was wrong. When I sat down, there felt like a strange clunk so I stopped to investigate.
For no better reason than it coming as I sat, I first suspected a saddle rail break, but those seemed fine. I banged hard on the saddle a couple of times and realised it was the rim bottoming out on the road
because I had a flat tyre - why I didn't check that first I'll never know.
I found a possible candidate for the cause of the puncture before getting the tube out, but putting some air in the tube indicated a hole in the wrong place
Checked the appropriate point on the tyre, but found nothing. My confusion finally lifted when I realised that I'd somehow turned the tube around when removing it and pumping it to check the hole location and it did, in fact, match where I'd removed the flint from. D'oh!
Puncture fixed, I contacted the group via OD and huggy to check the lay of the land. In the back of my mind I still had some uncertainty about whether I'd really found the culprit for my puncture or whether I'd be fixing again later on. The group were moving on to the curry house next door to the pub at this point, so I decided to ride towards home rather than away in case the worst happened (discretion vs. valour etc.).
I dithered a bit about whether to go straight home, or divert via either the Railway at Kelvedon or somewhere else for a pint nearer to home. Then I noticed a new rattly noise on the bike.
Another stop and a bit of fiddling around and I worked out that it was the two spacers between the seatstay bridge and the mudguard that were rattling because the bolt had come a bit loose. It's one of those that screws in from the mudguard side of the bridge, rather than at 90 degrees, so tightening it would require removing the rear wheel (again). I peered under the guard and felt around a bit before satisfying myself that there was little danger of it working far enough out to rub on the tyre, so decided to carry on with the plan of a pint somewhere before home.
I settled on the Swan at Little Totham, and got there in time for a couple of Captain Bobs before toddling off home via a route I used to ride a lot more than I have recently.
0% of the initial mission accomplished, but around 26 miles of cycling on a night when short sleeves were (just about) OK for the entire evening.
I blame the forward planning.