I can't seem to sort out the morning wee issue

Hi everyone, I hope you're all doing well. I posted a few months ago about the house-training struggles I was having with my Border Collie (he’ll be 12 months old on the 26th).

There's been a massive improvement since then as he now does several wees every walk (in my other post, he was only going once per outing) and the accidents in the flat have almost stopped.

I say "almost" because there’s still one morning wee that I can't seem to manage. He often doesn't give us any time to react once we're awake and just goes in the flat.

Does anyone have any tips? His last walk is at about 9pm (I can't do it any later due to work) and he usually goes out for his first walk of the day between 5am and 6am.

Thanks everyone.