That clergyman seemed familiar for a reason and I'm now almost certain that he is John Collins.
This would have been exactly the sort of thing he would have been involved in. He was a founder of both War on Want and the Campaign for Nuclear Disarmament, prominent in the anti-apartheid movement and a member of the Anglican Pacifist Fellowship. Despite all this, and his developing views on bombing and war in general, which were diametrically opposed to Harris', the two men remained on civil, friendly terms.
It was Collin's wartime experience with the RAF, and maybe his association with Harris, which led to his fairly radical views in later life.
Harris would later suggest that it would be a mistake to cease production of the Hampden, which he described as "a simplified construction type", in favour of the "over complicated, under-defended Halifax".
There was mutual respect and Harris stood by Dowding following his removal after the BoB. Indeed it was Harris who would later call him "the only commander who won one of the decisive battles of history and got sacked for his pains."
The problem was caused by various factors, but the most important had nothing to do with the defences. It was simply the obscuring of the aiming point by smoke and dust raised by the first Groups to bomb.