A Bank of England One Pound note (Series D - green)(Chief Cashier J.B. Page - serial 54X) 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 to £3 GBP.
A reputable coin dealer will be able to give a more accurate valuation.
Please check the serial number and provide the name of the Chief Cashier if possible.
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.
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.
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.
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.
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.
Without knowing the serial number, your 1952 Bank of England white Five Pound note could fetch up to £200 GBP in mint condition. The Chief Cashier was P.S. Beale.
Because it is a long withdrawn banknote, the Bank of England will honour it to the value of Fifty Pounds. As far as any collector value is concerned, it would depend on the Chief Cashier, serial number and condition of the note.
Without additional context, the value of a Bank of England Ten shilling note with serial number 18Y 015906 would depend on factors such as its condition, rarity, and demand among collectors. I recommend consulting with a currency appraiser or a numismatic expert for a precise valuation.
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 One Pound note (Series C - green)(Chief Cashier J.S. Fforde - serial S54L), uncirculated and in absolute mint condition could fetch anything up to £6 GBP. If it has been circulated but still in good condition, it might fetch anything up to £4 GBP. A reputable coin dealer will be able to give a more accurate valuation.
A Bank of England Five Pound note (Series D - blue)(Chief Cashier J.B. Page - serial 02N), uncirculated and in absolute mint condition could fetch anything from £5 up to £30 GBP. If it has been circulated but still in good condition, it might fetch anything from £8 to £15 GBP. A reputable coin dealer will be able to give a more accurate valuation.