Odd job man gives fine performance with old tailless mongrel going head over heels (8)
I believe the answer is:
factotum
'odd job man' is the definition.
(person charged with various jobs)
'fine performance with old tailless mongrel going head over heels' is the wordplay.
'fine performance with' becomes 'fact' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'tailless' means to remove the last letter (the tail of the word is removed).
'mongrel' becomes 'mutt' (both can mean a dog).
'going head over heels' says the letters should be written in reverse.
'mutt' with its final letter taken off is 'mut'.
'mut' in reverse letter order is 'tum'.
'fact'+'o'+'tum'='FACTOTUM'
'gives' is the link.
Can you help me to learn more?
(Other definitions for factotum that I've seen before include "Employee who does all kinds of work (8)" , "Versatile employee" , "Assistant doing all kinds of work" , "Dogsbody" , "One who does all kinds of work" .)