So I have an update.
I have been night boxing the rooster and that is going well. He doesn't like it much but it seems like a fair solution for now, even if only temporary.
I spoke to the Council official today. I now believe I know who complained (not fence burning guy). The official couldn't tell me, but it was unsaid iykwim. Also yesterday I passed the neighbour's house and he was by his front door. I waved a cheery hello and he mumbled and scuttled indoors quite quickly. Ordinarily we would have a nice chat. So I knew it must be him, all embarrassed to talk to me.
Anyway. Council official was really nice. He explained that they look at the context. It is a rural community and they have no problem with me keeping hens or roosters. I do have to take reasonable steps not to cause a noise nuisance though. So location of the coop to adjacent properties etc is a factor, as is how close the houses are to each other and the location itself.
I explained I was trying to rehome him, and he said that was a bit drastic and they would never ask me to get rid of the rooster, but I should take steps to reduce the noise if I could. I explained about putting him in the night box further away in the garage and he said that was perfect!
I also explained that in 15 years I've never had any complaints from the neighbours, and that my chicken keeping predates the neighbours moving in, so I was utterly shocked to find out about this one. He said he was satisfied that I was a good neighbour, reasonable and willing to work with them to find a solution and he would write to the neighbour to tell him they have no problem with me keeping the rooster and that I have taken steps to resolve the issue, so the Council will take no action and he can stfu now. Ok, I added that last bit!
I also asked him to write that the neighbour should just come and talk to me directly if he has any issues, because I'm a decent person and want us all to get along in the village.
He was really nice, and I'm so glad I spoke to him rather than just pinging emails back and forth. He out my mind at rest and I feel like I've had a small victory in winning over the Council!
You catch more flies with honey than vinegar!
I'm going to go talk to the neighbour next and gloat, sorry, smooth the waters, haha, and explain about the box. I shall enjoy being super sweet and pleasant and making him squirm, because the coward obviously thought I'd never realise it was him.
Anonymous keyboard warrior, that is what he is.
What he doesn't know yet is that some of my chicks are boys and I'm planning on keeping one or two. I'll perhaps set up one or more extra night boxes if I think that is feasible long term (just for the summer months). They are teensy tiny banties, so hopefully not loud anyway. Am I asking for trouble? Part of me wants to quietly rebel!