I stopped expressing at work when G was 14 months old. I had dropped down to once a day and was only getting about 60mLs, so having to top up his bottles with cow's milk. He drinks two bottles of dairy at daycare and most of the time will indicate he wants a boob when we get home from work. then he has a feed after dinner before bed, wakes around 11:30pm and again around 6am.
His brother was sleeping through the night by 12 months but G is still waking at least once. I think it is because he is still trying to catch up all the weight he lost when he got so sick his first 2 months in daycare. He's still tiny and light compared to his peers, where he was around average before. So because of that I'm not trying to night wean him yet.
With E I was exhausted when I returned to work and it was necessary to attempt some form of night weaning. My method was simple - I used to refuse to feed him if he woke before midnight... Would just go in and try to resettle him, then leave. If it was after midnight I'd feed him back to sleep. After a while he got the idea and gradually slept longer and longer until finally he slept all night. As I recall I had to get up to check on him that first night, make sure he was still breathing!!
With G I've not been as tired. I think I'm now used to operating with broken sleep and less sleep. And more coffee. Hopefully I can continue at night for as long as he needs me to, to catch up to his peers. I have my fingers crossed its not too far away!