"I do, if she wakes in the night I don't put on the light, talk to her, or pick her up (unless she's really distressed, I'm not mean) This way she doesn't wake up fully and is easier to get back to sleep. I haven't changed a nappy at night for months now"
This makes me so sad.
Close your eyes and imagine wearing a nappy, imagine the feel of it against your skin. Now imagine it being filled with cold urine. Imagine tossing and turning, imagine the feel of the wet plastic rubbing against your skin and genitals. Imagine it sticking to your bottom... Is that comfortable? No. Maybe it isn't so uncomfortable that you scream the place down (become "really distressed"). Maybe you don't make any fuss about it because you have learned from past experience that your fuss isn't going to change your situation. Either way, it still feels like crap.
It doesn't make sense to me that a wet baby would ever feel as comfortable as a dry one, so I would always change a wet baby at night as well as the day.
While it seems sensible not to put the light on, talk, or play at night time, I do not think that you should stop touching or cuddling your baby because it's dark outside. I'm certain that this is effective in getting them to stop asking for comfort (and waking you up so often), but at what price?
Mine have never cried specifically because I've changed their nappy - but they would certainly have done if they'd been left wet, or if I hadn't soothed them back into a sound sleep afterwards. They definitely would have screamed like your lo if I hadn't nursed them back to sleep - because this was the way they had been put down to sleep in the first place. I'd probably be stumped if you told me that you just put your baby down on his own in his cot for bed and then he cried when he woke up in exactly the same environment. But I could understand he would expect to be cuddled back to sleep if this is the thing he remembers doing before he drifted off. He might also scream simply because he's been woken up - sometimes I feel like doing this and I'm a grown woman! But please don't let this convince you not to night change - just be gentler or quicker or change him on your knee etc. It's very unlikely that he wouldn't wake up and do the same thing if you left him wet anyway (unless you ignored his needs consistently enough to ensure that he gave up asking you to fulfill them).
Can you give some more information about your night time routine? How do you put him down to sleep? Where does he sleep? Does he tell you he's wet, or do you change him at a particular time (like before you go to bed yourself)? Does he wake up completely when you're changing him? Are his eye's open or closed when you've finished and have to pick him up? Anything else?