A British 197? One Pound note (Series D - green)(J. B. Page - serial 16U), uncirculated and in absolute mint condition could fetch anything up to £5 GBP. If it has been circulated but still in good condition, it might fetch anything up £2 GBP.
A reputable coin dealer will be able to give a more accurate valuation.
John Page was the Chief cashier of the Bank of England from 1970 to 1980.
You do not specify the Chief Cashier or the type of One Pound note. A Bank of England One Pound note beginning with Serial 37J could have been - 1934 - Chief Cashier K.O. Peppiatt - Series A green - Britannia on the front and the Bank of England building on the reverse. 1960 - Chief Cashier L.K. O'Brien - Series C green - QEII on the front and Britannia on the reverse. 197? - Chief Cashier J.B. Page - Series D green - QEII on the front and Isaac Newton on the reverse.
If your Ten Shilling note has Queen Elizabeth II on the obverse and a large image of a seated left facing Britannia on the reverse, a serial number commencing with S74 would be Chief Cashier J.Q. Hollom, possibly printed in 1963.
Please check the serial number and provide the name of the Chief Cashier if possible.
The banknote you describe does not exist. G.M. Gill was Chief Cashier of the Bank of England from 1988 to 1991. Please submit a new question including the serial number of the note.
1949 TO 1955
You have omitted the first 3 or 4 characters of the serial number and not provided the name of the Chief Cashier. Modern Bank of England One Pound notes were issued from 1928 to 1984. Please narrow down the possibilities a lot.
Some of the very much older banknotes will have the date of issue prominently displayed on them. Alternatively, the first step is to identify the Chief Cashier which will place the note into a range of years for which that individual was the Chief Cashier of the Bank of England. Second step is to identify the leading characters of the serial number. With this information, you can consult a banknote catalogue and come fairly close to the year of issue.
A Bank of England 1971 One Pound note (Series C - green)(Chief Cashier J.B. Page - serial S89M), uncirculated and in absolute mint condition could fetch anything up to £25 GBP. If it has been circulated but still in good condition, it might fetch anything from £6 to £10 GBP. A reputable coin dealer will be able to give a more accurate valuation. A combination of the Chief Cashier and the serial number can pin the note down to a year or two.
A Bank of England 1940? Ten Shilling note (Series A - red/brown)(Chief Cashier K.O. Peppiatt - serial E53D), uncirculated and in absolute mint condition could fetch anything up to £65 GBP. If it has been circulated but still in good condition, it might fetch anything from £20 to £34 GBP. A reputable coin dealer will be able to give a more accurate valuation.
A Bank of England Ten Shilling note (Series A - red/brown)(Chief Cashier L.K. O'Brien - serial number B15Y), uncirculated and in absolute mint condition could fetch anything up to £40 GBP. If it has been circulated but still in good condition, it might fetch anything from £10 to £18 GBP. A reputable coin dealer will be able to give a more accurate valuation.
A Bank of England 1975 Ten Pound note (Series D - brown)(Chief Cashier J.B. Page - serial B56), uncirculated and in absolute mint condition could fetch anything up to £40 GBP. If it has been circulated but still in good condition, it might fetch anything up to £25 GBP. A reputable coin dealer will be able to give a more accurate valuation.