I wish I had a pound for every time I hear the phrase 'little tin gods' in reference to planning department staff.
I had many of your problems when trying to get outline permission on a small plot i still owned from the smallholding my late partner and I had in Aberdeenshire. It was about a fifth of an acre and had an old railway carriage and a wooden garage, and caravan hardstanding on it, with previous access to a field we had owned but sold to the adjacent farmer previously (I wish we had taken a loan to survive my partner's redundancy instead of selling that field.)
One planning officer when I was applying for a new house opposite it said 'that's where you should build your own house - perfect infil site and a great view.'
I had moved down here to central Scotland to be nearer my children in the middle of the process of trying to get approval. It appeared that as soon as I moved away I became 'persona non grata' with my ex neighbours (who I seriously believed had been my friends
).
They started putting objections in, and were apparently seeing animals that I had never seen there in 12 years - red squirrels, pipistrelles in the trees etc. (the bats had been living in our roof space so it was highly unlikely they had moved) They persuaded the council to put a TPO put on first the whole plot, saying it was a shelter belt, then on the weed trees I intended to remove so I had to have the layout changed - twice
Fortunately I was treasurer of a smallholding group and one of our members was a planning consultant. He offered his services for a much smaller fee than normal, and sorted it all out for me, and the planner was reprimanded, and the objections rejected, but not before I had to spend a lot of money on various environmental reports, and update the arborial one I had done years before which stated the weed trees were unsafe, due to being on a mound, ivy growing through them, large holes in teh trunks, split trunks etc etc. The council environment guy had said they were perfectly all right. So three of the TPOs remained - supposedly for all time
I eventually got consent, sold the plot, at a reduced price because of the TPOs and the new owners managed to get permission to chop the trees down. They knew someone influential it seems!
So don't give up. Beat them at their own game. Get all the evidence you can. A lot of the time they are lying, procrastinating, or just being bloody minded! And remember that by law, all council meetings have to be minuted - even within departments. The Freedom of Information Act is brilliant! Go for it!!!