OP, why do you say "I don’t get (or expect) much on the day".
I think you need to start expecting a LOT, I mean a LOT. So this year, if you want to prove he will forget, then let him forget, and then ask what he plans to do to make up for it. Not a small gesture, a big gesture. He needs to get on the Internet and find a fancy restaurant or weekend away. He needs to treat you beautifully.
And next year, he will, remember! Otherwise again, big big gesture.
"He is crap at the small things (never bringing me cups or tea even though I always do for him and tell him how much it means to me, mothers’ days cards made at lunchtime after reminding etc) but I think they are important. AIBU to not remind him?"
You are not being unreasonable to remind him. However, why is he not bringing you cups of tea etc? Does he just wait for you to make them, or does he not drink them, or does he make them just for himself?
"He will accuse me of “setting him a trap”. I kind of am... but it might be a good lesson?! " Setting a trap would be putting a £10 note on the floor over a bear trap, you are not setting a trap. You are seeing if your life partner can remember your bithday!
"So AI-also-BU and shallow to wish I had a romantic thoughtful husband too or are some men just not that way and never will be?"
My opinion is that some men are not romantic and they get away with it because their partners are not bothered (some women too). But if it does bother you, then maybe you need to let him know.
Do people honestly think you are'...being unreasonable and tricking him'?? he is an adult. He knows you have a birthday, if he cannot remember it that sounds like he has a problem. he has a phone, a calendar, a diary, a pen and paper....