Thanks so much for your responses ladies, I realise that this is a common issue during this transition, its just so frustrating.
Cold turkey was definitely my plan but we are in a vicious cycle at the moment as he is so tired from the short and/or disturbed nights that he crashes in the car and because he is now back at nursery 3 mornings a week, it is impossible to avoid! (However when he dropped the nap he was sleeping so much longer at night that he managed the car journeys no problem, so I know that he can do it when well rested)
Again, just like yesterday, he just fell asleep for 20 mins on drive home.... and he has never gone to bed in less than 7 hours from a nap, so we are looking at another long day and overtired rubbish sleep.
I have no issue using SUPER early bedtimes (did 5pm recently) - but even 5 minutes of sleep in the day throws that option out of the window.
He is still breastfed to sleep most nights, but can fall asleep independently no problems and was STTN with no issues until very recently.
NWs he just screams and screams for me and then either settles as soon as I lie down next to him if it is early in the night, or on one of the long ones (which tend to be 4am onwards) just tosses and turns next to me or asks to get up, but listens when I say it's time to sleep and tries but can't.
He asked for a feed at 4am a couple of days ago, which is very unusual (hasn't had nightfeeds for a very long time).... and he went back to sleep after feeding, so I guess was either teething or hungry? So maybe there is more to this than just the transition?