Stanley Gibbons Pages For Great Britain

I never thought I would be a collector of Great Britain (GB) but in a large lot I seem to have acquired a red Stanley Gibbons with much of the 1960's through 1980 in crystal mounts. (75% MNH) I also have a ton of used loose.
In the book there are supplement pages for the catalog renumbering. I have found that some pages are straight replacements but then there is, for instance;
page 41p; which on the left bottom corner says '78 SPT Extra leaf to follow page 41'. Next is page 41p that has the inscription on the bottom left '80 SPT Extra leaf to follow page 41'.
The only difference between these two pages is that the latter has SG numbers beginning with an X. Example is X855 vs. 855 on the former page.
Is this an additional page or is duplication?
Where is a good place to find out which pages should or should not be there?
Then, I look at page 42 and it has same freakin' stamps on it!!

Clues????

Occasionally GB stamps need "re-numbering" or otherwise some stamps would have many, many suffixes following the S.G. catalog number. The X prefix numbers refer to decimal Machin stamps... for instance a stamp with a catalog number S.G.922 would refer to a decimal commemorative stamp issued in 1973. A stamp with a catalog number S.G. X922 refers to a 50p decimal definitive with all the definitives in that series given an X prefix as it is/was an ongoing series. That is a simpler solution than renumbering every stamp in the catalog.

Thank you! I am trying to figure out the values, what they mean along with the markings. For instance; what does 1'6 mean?
I just found a "Stanley Gibbons Great Britain Concise Stamp Catalogue 2007" for 78 cents plus shipping on Amazon. So of course I bought it. Hopefully it will help on matters like this.

The SG Concise is probably the most used catalog. The supplement pages you refer to may in fact be for the Specialised Catalogue which is slightly different to the Concise. The Concise does not list or catalog every paper type, phosphors colors etc but will give the band position types (left band, center band etc).
I'd say the 1'6 refers to old currency before decimalisation being one shilling and sixpence. A photo/scan might assist.

The "1/6" value is from the old British currency of pounds, shillings and pence.

1 pound = 20 shillings
1 shilling = 12 pence

1/6 was 1 shilling and sixpence.

2/9 was two shillings and ninepence etc.

The forward slash (or "solidus") was originally a long "s" for shilling (or for "solidus" in Latin).

By decimalization, does that mean that 1/6 = 18p. Basically in terms of denomination; Only one type of currency. It would be 1.5 Shilling or 18 pence.

No, decimalisation in the UK kept the pound the same value and divided it into 100 (new) pence or 100p.

That meant that one shilling became 5p, 1/6 (said as "one and six") which had been worth 18 old pence (18d) became 7½p, 2/- (two shillings) became 10p and so on.

ok, so 1 pound = 20 Shillings = 100 Pence.
So we need to know both numbering systems?
What year was the change?
(edited to reference) I found the info!!
http://en.wikipedia.org/wiki/Postag...reat_Britain

The UK pre-decimal coinage was a complicated affair with there being 12 pennies in a shilling and 20 shillings in a pound but the only thing to remember is that before 1971 there were 240 pennies in a pound. From 1971 there is now 100 pennies in a pound... so obviously a decimal new penny is worth 2.4 old ones.

It is much easier to figure once I realized it was originally a division of weight. 240 silver pennies actually weighed one pound. It's no wonder the decimal system went well, as the penny was now worth more, and easier to count. No scales needed.

Or was it that a pound was worth less? LOL

It has to be noted that the silver 1:12:240 was a common ratio in many European countries too and while most turned to decimal the UK was very late on the decimal scene... unless you count the two shilling piece (one tenth of a pound) which was a Victorian "attempt" at decimalization.
The smallest denomination GB postage stamp was the half-penny, first seen in Queen Victoria's reign, and was half the size of a penny stamp.

Some British colonies also issued farthing (quarter penny) stamps.

... and, of course, there was the strange denomination of One Penny Farthing (1 penny plus 1 farthing) on a GB Queen Victoria postcard. The only time a farthing featured on GB postage.

So which is the predominant currency; the Pound or the Euro?

Something like 25 countries in Europe use the Euro as their common currency. The UK still uses the Pound. I cannot speak for the rest of the UK but in Scotland the Euro is accepted and welcomed in many places such as hotels, restaurants, tourist areas etc.