identifying the age of a Raleigh?

I know this is a bit of a cliche thing, but could do with some help!
Am restoring a New Holden badged bike, nice old handlebars, heavy frame but with lots of character, I know that Raleigh took over the company in 1957 (like lots of other companies BSA etc etc) and that these were only around until 1963- so got it between those dates.
No Sturmey Archer 3 speed to use to date the bike, the last guy has swapped to nice modern wheels (700's), there is a frame number and stamped on the seatpost bit something like LA1235? which I just can't google to find a good guide or any codes like that at all, the only other thing I've got is the BB spindle has 16CG which I believe is the generic name for the part and stamped with a large letter "P" I know 1951 has the letter "A" anyone got any idea?

p { margin-bottom: 0.21cm; } "as determined by the "51" stamped into the Sturmey Archer 3 speed AW hub. I... for the bottom bracket assembly from the bike which includes the cottered axle, both bearing cups, the lock ring, and the bearings. The axle is stamped "A-16G.C"