Rarerims - I can help you out a bit with dates! First off though, great finds!
With regard to the first set - good news, it is complete! Below is the catalogue page showing your set! The presence of 9 sockets suggests they are BA sizes which makes your set an NA 110C!
I would suggest it dates from the early 70’s. Much earlier and the box would be finished in the classic crackle finish, and probably the right size too! Much later and the logo would have been changed. Good era! Although Britool had been taken over by James Neil, they had yet to start the creeping cost cutting that eventually did for the company!
I think you’re right and the second 1/4 drive set dates from the 80’s. I would suggest late 80’s or early 90’s as up till then the spinner handles were a hard shiny plastic. Seem to recall they switched to the softer, matte (Spiralux?) handles in the late 80’s.
Yes, that 3/8 set is superb!
I suspect late 60’s! Again, any earlier and the box would be red crackle finish (I say red, they were actually red and black, but the finish was quite striking), and the tools seem to be bang on for late 60’s. The ratchet handle looks to be from that era and you have the ‘flush fitting’ sliding T that was discontinued in the mid 70’s!
I have seen very few boxes in that hammered finish. The first time I saw one I assumed it was a repaint, but I’ve seen enough now to be sure they came from the factory like that, and yours is one more piece of evidence as it’s obviously original, complete with outer! My dad bought basically the same set, in I think about 1965, and that had the classic crackle finish. By the early to mid 70’s they were all going out in plain red boxes like your first 1/4 drive set, so I’m thinking your set dates between the two!
The combination spanners are superb. As good as Britool ever made. They’re older though - I’m thinking perhaps 50’s. I’ve certainly seen similar tools from that era!