Thanks both.
During discussion, last minute of course, I noticed the planners were confusing two terms defined in the glossary of the GPDO and made them aware they were misinterpreting the meanings. Our interpretations of this are opposing of course as I want planning permission and they don't want to grant it, but they were confusing terms and mis quoting the GPDO. Low and behold, communication halts, 36 hours later a refusal is issued. According to the properties and title of decision notice PDF, the author of the decision is a planning officer in the north east. Presumably she was drafted in last minute. Lots of her stated facts are inaccurate or plain wrong.
It's fairly complex as we are in Green belt but I have case law to support my case, although they reviewed it and simply disregarded it. Appeal is my only way forward but wondered if there was any merit in giving weight to the procedural errors. I don't want to appear petty, but I would expect to be pulled up on similar errors. It all feels hastily cobbled together, the section of the GPDO quoted in the refusal is entirely different to the one quoted two days before and both planning officers went on leave the following day.
Good idea, I will redact the notice and upload it. Thanks again.