Left old friend casing clubs in the area (7)
I believe the answer is:
Here is my best explanation:
'in the area' is the definition.
'left old friend casing clubs' is the wordplay.
'left' becomes 'l' (common abbreviation**).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'friend' becomes 'ally' ('ally' can be a synonym of 'friend').
'casing' is an insertion indicator (I've seen this in other clues).
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'oally' placed around 'c' is 'ocally'.
(Other definitions for locally that I've seen before include "Nearby", "Happening in neighbouring district", "Within a particular area", "In the immediate neighbourhood", "In the surrounding area", "In the vicinity" and "Near home".)