Thanks for your great detailed response i should clarify that I am primary carer and have spent the last 6 months as stay home dad with the kids, so my partner have both taken on an equal share of dealing with the kids at night - with there being two it’s usually my partner takes ones I take the other up until now. Honestly our youngest who is nearly 1 has been the complete opposite to our oldest child, sleeps like an angel - 4yo wouldn’t sleep through the night or stay in his own bed even if you paid him 🤪

I do have the support of my partner but she tells me to put my phone down and try and go to sleep - which with all respect to her is the least bit helpful because I can’t sleep so what do I do, lay there and stare at the ceiling fan? 
Our kids both wake up at 5 like clockwork, so I just think just make it until 5