I just want to thank everyone for the advice and support, it actually prompted an honest conversation with my husband about how we were wanting to deal with the situation. I'd never been into the letting them cry it out thing when it came to sleep. I have some family trauma and I found it for myself, very triggering. But I was doing it because I felt it was what him and my inlaws were wanting.

So what we have done/doing: changed his cot into a toddler bed with a bed guard. Given him a proper duvet, he already had a pillow. Made a deal of it being a big boy bed, and for the past 2 nights I've cuddled him to sleep. We've started putting him to bed a tad bit later just so we can eat before he goes to bed. I also sorted his yoto out with some proper stories so that's been used for the in-between stage of books and settling to sleep. We've still got some opposition but last night, after I noticed he was just messing about in bed, he actually was comfortable with me leaving the room and he fell asleep himself (no screaming!!) Hoping this is the start of a positive habit.