import re
s = '\n £1,000.73 \n\n\n + £1.26\nUK delivery\n\n\n'
r = re.compile(r'£(\d[\d.,]*)\b')
print([x.replace(',', '') for x in re.findall(r, s)])
aW1wb3J0IHJlCnMgPSAnXG4gICAgICAgICAgICAgICAgwqMxLDAwMC43MyAgICAgICAgICAgICAgICBcblxuXG4gICAgICAgICAgICAgICAgKyDCozEuMjZcblVLIGRlbGl2ZXJ5XG5cblxuJwpyID0gcmUuY29tcGlsZShyJ8KjKFxkW1xkLixdKilcYicpCnByaW50KFt4LnJlcGxhY2UoJywnLCAnJykgZm9yIHggaW4gcmUuZmluZGFsbChyLCBzKV0p