Turning the southeastern corner of Wales coincided perfectly with the beginning of September – new term, new season, new compass point to follow. The middle of the day is still as blazing hot as some of those heatwave days of July, but the dew is getting heavy and the shadows are cold. I’ve cheered right up since the woeful drowning-in-green of a few weeks ago – almost as soon as I left Hay-on-Wye I felt a kind of pull, like invisible surface tension, drawing us towards the Severn estuary and the end of the 182-mile border. I also realised that I was worrying about being cold in November, at the very same time as burning my eyelids in August – someone needs to take a little of their own advice about living in the moment.

We’ve stayed for a rest day and a half near Caldicot, at the house of Jez, Jo and little Jeanie. Jez is in the process of walking around the whole of Britain, something like 6440 miles, which he is documenting as films of the journey overlaid with audio of conversations he has along the way, as well as with a GPS line. Jez sees it as a kind of drawing, and it’s been great to stop here and let our adventures sniff each other.

Jeanie is seven before the end of the month and went back to school yesterday morning – she goes to the local Welsh language primary, one of only two in the whole of Monmouthshire. There’s not a lot of Welsh spoken down here, where the closest city is Bristol and Herefordshire and Gloucestershire are very near by, but the school is growing, and in next-door Newport there are several Welsh schools that are experiencing a kind of heyday. Jez and Jo, neither of whom speak Welsh, are really proud that Jeanie now does, and Jeanie shrugs and gets on with it, as kids do. Jez called up the head, Diane, and offered to send the donkey round, and so this morning we followed Jeanie to school, and Chico, aged about the same as the reception class, attended his first assembly.

I explained the adventure, in Welsh, feeling somehow more nervous than talking to Radio Cymru. It’s not far off a quarter of a century since I was in primary school, but the little things come steaming back across the decades – art on walls, little toilets, squeaks on hall floors, disinfectant, carpet tiles, the smell of school dinner, morning hymn-singing – and render me an uncomfortable child again. The hundred-plus kids asked good questions in shy whispers: Why? Where do you sleep? Were you lonely when you walked around Anglesey without the donkey? Are you going to walk past my house? Have you been to Mwnt? I answered as best I could, which was pretty badly.

We’d camped in Hotel de Wheels, J&J’s camper in the garden, under the treehouse and between the hammock and the raspberries, and were as taken by surprise by schooltime as I was every day of my school life, getting up too late and running about their house jamming bread in the toaster, wet clothes in the dryer, phones on to charge, all at once. So I arrived at school addled, undercaffeinated, and very out-of-practice, having barely encountered a Welsh-speaker since Bangor, or an appointment since March.

While telling a boy that we’d already passed his house, I attempted to suggest that he see if he could spot any little piles of tell-tale Chico chocs left behind. A sea of blank faces, including the teachers’, gazed at me, and I began digging the hole, realising too late that I didn’t know the child-friendly word for poo. Eventually I hit on ‘cachu’, which I fervently hope isn’t quite as bad as saying ‘shit’ in school assembly, but I think is. Oh dear.

Chico did a walkthrough in front of class one, to a gratifying sound of gentle sighs of love and wonder, not in the slightest bit concerned about strolling around inside a school, having been practicing going in and out of J&J’s conservatory dining room all day yesterday. And then it was patting time, with each child feeding him a couple of horse nuts and Chico doing brilliantly among the throng of little people in quite a wide variety of school uniforms. The kids, presumably made braver by each other, fed him well – flat handed, but not so convex that the nuts roll off before Chico’s whiskery, dexterous lips can tickle them up. One girl enjoyed the whiskery feeling so much that she fed him her whole hand, sending it in, palm down, as if posting a letter. In the slow motion of horror I watched Chico clamp down on it; fair enough – kids had been posting food into him for ten minutes. Her face registered the mistake and, I suspect, the understanding that it was her own fault, because she didn’t make a sound and no one except her, me and Chico noticed it happen. It must have been a bit scary – he bit me a few weeks ago when I was being sloppy about the whole flat-hand thing, took a little skin off and left me with a slightly swollen finger joint. While he held it in his teeth it was like being in a vice – firmly held, and with much, much more power, pain and hospital visits possible if he felt like it. Those teeth have ground down branches the length and (some of the) breadth of Wales – they are not to be underestimated. Thank all the gods and most of all Chico that he let go, and the little girl thrust her fingers into her own mouth to comfort herself before getting over it and even feeding him a few more mini palmfuls before disappearing into the playground.

Only a little swearing and no lost fingers, and visiting time was over. With the camerabag full of carrots scrubbed to half their original size and donated by an enthusiastic dinner lady, and a plastic bag of Chico chocs to go, we left Ysgol y Ffin and hit the road.