Good luck, shifty! This might not be a bad first one, as it’s got plenty of Listener-esque play going on but doesn’t feature as obscure words or really fiddly clues that some can. It does need a lot cold-solving though!
The fifth across clue has an extra word. I wouldn’t usually describe it as a ‘plot’, but maybe an enclosed area for a particular type of produce.
The ninth across is not that kind of beat. In fact it’s a slightly obscure meaning for the word. Younger as you might put after a name, and the initials for a police force whose name has now changed, the whole thing turned backwards.
For the fifteenth across you need one who can get help and then reform to make a longer word.
The definition for the fifth down is the last three words.
I hope this helps ;-)