I've had this old Raleigh sports knocking around for a while. I thought I should attempt to date it but I'm having trouble. It looks like a 50s-70s model but the frame number has no letter prefix/suffix
What about other parts such as the wheel rims? Raleigh weren't mere bike assemblers, like manufacturers are today. Pretty much every part of a really old Raleigh will have been made in-house, from raw materials, at Nottingham. If you can find other Raleigh stamped components, they may be dated.
I've got a couple of 26" steel rims as recent as 1989 that are stamped Raleigh Nottingham!