Fruit delivered on horseback - it's a gentle run round (10)
I believe the answer is:
cantaloupe
'fruit' is the definition.
(I know that cantaloupe is a fruit)
'delivered on horseback it's a gentle run round' is the wordplay.
I cannot really see how this works, but
'a' could be 'an' and 'an' is found within the answer.
'gentle' could be 'p' (I've seen this in other clues) and 'p' is found within the answer.
'round' could be 'o' (round can mean a round object) and 'o' is located in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
This explanation may well be incorrect...
(Other definitions for cantaloupe that I've seen before include "Small melon variety" , "fruit" , "Small to medium-sized melon with yellowish flesh" , "Small melon with ribbed skin" , "Musk-melon" .)