Hi there
I am now part way through my build after getting PP about July time. I had a neighbour object for similar reasons as you state. I say object, it was more of a rant really!
When I found out the neighbours had objected, I took some pictures centred around their objections (overlooking, loss of privacy etc) and went on a charm offensive with my case officer. It went down very well with him.
My pictures pretty much blew their objections out of the water in that they demonstrated that their objections were not borne out. If the nearest neighbour who has objected is, I think you said, 45 ft away, take pictures of your property in relation to theirs etc with a view to playing down their concerns.
After my visit to planning, I very much felt the case officer was on my side. Yes he had to come out and visit and pander to the neighbours but I think my proactive action tipped it in our favour.
Some councils operate a objection threshold that when reached, means automatic referral to committee and others have referrals from councillors or the parish council. If it goes there, a group of councillors can decide emotionally rather than on policy which could cause a problem.
Generally, planning officers decide planning apps objectively on policy, not on rants from neighbours. Good luck