Thank you, my friend. I've removed the H1 tags from the menu buttons and added H1 to each title (most already were). Now trawling through and adding H2s. Making sure keywords relate to text on the relevant pages as I go.

I never really understood the use of H2 and H3, associating them more with screen reader tabbing. Interestingly enough, my other sites all seem to pick up the website/page titles, or at least near enough, without cross-referencing each one individually. This probably made me think I was doing everything correctly and showing the SEs who was boss

Thank you again. You are greatly appreciated.