Spear & Jackson No52 12" & its evolution

Hi Guys,
Alas I am sorry to say this time it is not a rare saw, it is rather a common saw, I would say modern, but I suppose, it is not that modern, being that it is almost 100 years now that it has been made.
I suppose there are going to be changes over the years, as working practices and materials change.
The No 52 has changed little other than the handle, it seems to have evolved over the years.
My observation is the type of steel used.
In the very first No52 saws the steel was Mermaid brand, I am guessing but were there more than one variety of mermaid brand, Extra & Extra Extra, I am guessing here, I am sure I have seen some thing close.
Then a little later on the No52 started to appear in Leap Frog Brand.
Last but by no means least, the picture here is of what looks to be a saw of modest age, now the other more modern style of handle has been around since the 1960's , I wonder if anyone fancies a shot at its age, the handle could be a lot newer than 1960, I suppose it might of been a special lot made to order so to speak.
Finally the steel in this saw is London Spring.
I wonder if that is common practice, use different steels as the years go by.

 

This is a particularly difficult saw to date, with the poll giving an unfortunate choice of dates (explained below)

The saw has the medallion, etch and overall style consistent with S&J's general 1950's or so production, but the softish looking, pale (new growth) beech, thin finish and lack of use suggests a younger saw, so I'd say 1960's, with a strong caveat... S&J redesigned their entire range coinciding with their 200th anniversary (1970 from memory), with simplified medallions, printing on saws instead of acid/electrolytic etches and awful handles, epitomised by the "batwing" handle fitted to their infamous "Black Prince" model.

So I'd guess this saw is from somewhere >1950 and < 1970. Which falls exactly between the two options given in the poll.

I never take much notice of the maker's claims as to the steel in saws, saw steel is only as good as the tempering and surface finish anyway. Most S&J saws, even the basic models, are good steel, but the ones you really want Steve are the double mermaid models.... they are unbelieveably hard and tough. Also look for ones labelled "New Process ... Sorbitic Temper... Super Special Saw Steel", they will destroy any file you can buy today.

 

Thank you Dusty, you gave me just the info I was looking for, yes, I can only agree with all you have said, the stamp to the spine, the type of etch, I think you must be close, the types of steel that you mention, I have seen a couple of these, there is one now on ebay as I referred to earlier the EXTRA CAST, nice little back saw, 14" Brass looks like the No26 possibly even earlier, I don't have the earlier catalogs to confirm, but I have not given up yet, haha
I am sure I have a couple of Panel saws with the kind of etch you refer to"Sorbitic Temper" , the earlier Sovereign Saws

 

S&J had their backsaw handles redesigned in about 1960, so I'd guess this as earlier, but not pre-war.

Simon