Not noticing he's misspelt "Leeds" in it (8)
I believe the answer is:
heedless
'not noticing' is the definition.
I can't tell whether this definition defines the answer.
'he's misspelt leeds in it' is the wordplay.
'he' becomes 'hes' (I am not sure about this - if you are sure you should believe this answer much more).
'misspelt' indicates anagramming the letters (I've seen this in other clues).
'in it' means one lot of letters goes inside another.
'leeds' with letters rearranged gives 'edles'.
'hes' going around 'edles' is 'HEEDLESS'.
Can you help me to learn more?
(Other definitions for heedless that I've seen before include "Inattentive, unmindful" , "Imprudent" , "Incautious" , "Taking no notice" , "Unconcerned" .)