Here is a wikipedia history
The first Bank of England ten-shilling notes were two-sided, red, printed banknotes featuring the declaration "I promise to pay the bearer on demand the sum of ten shillings" on the front. This declaration remains on Bank of England banknotes to this day. In 1940, during the Second World War, ten-shilling notes were issued in a new mauve and grey colour scheme in order to deter counterfeiters, although the design remained the same. At the same time, a metallic thread running through the paper was introduced as a security feature. After the war ten-shilling notes were issued in their original red colour. The earliest post-World War II notes did not have the metallic thread security feature, but those issued from October 1948 onward did.[1]
A new design for 10/- notes was introduced in 1961, with the old notes ceasing to be legal tender in 1962. These new series C notes were slightly longer and narrower, and were the first 10/- notes with a portrait of Queen Elizabeth II on the front. The reverse design incorporated the logo of the Bank of England.[1] In the late 1960s it was decided that future banknotes should feature a British historical figure on the reverse. The first such note was the series D £20 note, first issued in 1970, featuring William Shakespeare. A design for a 10/- note featuring Walter Raleigh on the reverse was approved in 1964, but this was never issued.

Instead, in 1969, as part of the process of decimalisation, a new fifty pence coin was introduced as a replacement for the 10/- note. The principal reason for the change was economy: the notes had an average lifetime of about five months whereas coins could last at least fifty years.[4] The series C 10/- notes ceased to be legal tender on 22 November 1970.[1] In the Isle of Man, both the English and Manx 10/- notes continued to be legal tender for 50 pence until 2013.[5]
Details
Image Note First Issued Last Issued Ceased to be
legal tender Colour Size Front Back Additional Information
[1] Series A (1st issue) 22 November 1928 Unknown 29 October 1962 Red-brown 138 × 78 mm
[2] Emergency wartime issue 2 April 1940 Unknown 22 October 1962 Mauve and grey 138 × 78 mm Incorporated metal thread for the first time; same design as series A

Series A (2nd issue) 17 June 1948 Unknown 29 October 1962 Brown 138 × 78 mm Reissue of unthreaded pre-war notes
[4] Series A (3rd issue) 25 October 1948 Unknown 29 October 1962 Brown 138 × 78 mm Metal thread introduced permanently
[5] Series C 12 October 1961 13 October 1969 22 November 1970 Red-brown 140 × 67 mm Queen Elizabeth II Bank of England logo First 10/- note to carry portrait of monarch
AND here is a retail site to check (has pictures)
https://www.thebanknotestore.com/di...ankofengland