Some people swear by Nytol products:
https://www.nytol.co.uk/
(I tried the tablets many years ago and all they did for me was to give me an incredibly dry mouth. However there are more products in their range now, so perhaps I might try a different one at some time in the future).
This web page looks useful. It includes mention of herbal remedies that might help you:
https://amerisleep.com/blog/natural-insomnia-remedies/
I find this a pleasant and relaxing drink
https://www.yorkshiretea.co.uk/brew-news/our-cosy-new-bedtime-brew
and any milky drinks, such as Horlicks, are said to be good at aiding sleep. (So is cheese by the way. It seems that it's a myth that eating cheese before going to bed disturbs sleep; it actually aids it).