Beautiful area mum fences off against slugs (5,5)

'beautiful area' is the definition.
(picturesque area of south eastern England)

'mum fences off against slugs' is the wordplay.
I cannot really understand how this works, but
'off' could be 'out' (both can mean wrong or inaccurate) and 'out' is present in the answer.
'mum' could be 'sh' (both are used to tell someone to be quiet) and 'sh' is found within the leftover letters.
'slugs' could be 'downs' (slug can mean to down or knock over) and 'downs' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...