evidently quite acceptable

At worst, he could have hated it. Or fallen out. Or climbed out deliberately. As it was, only a few stops were required to pick up his hat and refit it until we found that tucking the back-of-the-neck-covering Legionnairesque flap into his jacket and pulling his hood up over the hat prevented it from being too easily removed. I'll have to find something stronger than Velcro to attach the cushion to the seat by his left elbow (after he discovered he could pull it off) and tape over the rip in my saddle (to prevent him trying to pick at it and potentially getting his fingers trapped beneath my arse) and devise a means of stopping him kicking me in the back of the upper thigh (not painful, but if he stretched out his legs it prevented me from pedalling properly, thanks to my bike's frame's stupid compact geometry) but it was generally quite a success, especially after I stopped attempting to use the stupid wheel-twisters at our destination and chained up to the trolley-shelter which left plenty of spare cable to loop through the seat. More trips during the evening this week, possibly including his first jaunt round the hill.