Hi,
Thank you for your responses.
Jean Meeus gives a time of the spring equinox in 2019 to be 21:59:34 TD in his Astronomical Tables of the Sun, Moon and Planets, 3rd Edition (p.151). Taking Delta T is be 69 s currently and subtracting this value gives 21:58:25 UT. Rounded to the nearest minute this is 21:58 UT.
John