I do not think pasteurisation affects fat content?

Homogenisation is a separate process and it is possible (at least in the UK) to buy not homogenised pasteurised milk which should have the same far content.

To me filtered milk (which is filtered to remove bacteria and other things before pasteurisation to keep it fresh for longer tastes very good, which favours the argument it is the freshness that matters.

It doesn't but processing does. I think some dairies extract the fat and re-add it later to a consistency. That's why I don't buy retail milk and do a farmer-consumer milk-man! :)

Yep! Can confirm that the fresh milk from my grandfather's cows is tastiest before being run through a separator to remove the fat.