Dr Ivan D. Reid ) gurgled happily, sounding much
like they were saying :

let me go. I was quite relieved as I thought the inspector was
reasonable and understood my circumstances. I went to the tube
station and bought the day travel card (yes, including the zones
where I was on the bus), and soon forgot about the incident.

Something doesn't ring true. Any travelcard is valid on (almost)
any bus[1], so you need pay no extra for "zones on the bus".

IRTA having got the bus from (say) Zone 4 to a Zone 3 tube station and then
buying a travelcard including Zone 4.

Would a Z1-2-3 travelcard cover bus to Z4?