Head describing Scottish town preacher (3,6)
I believe the answer is:
lay reader
'preacher' is the definition.
(I've seen this before)
'head describing scottish town' is the wordplay.
'head' becomes 'leader'.
'describing' indicates putting letters inside (describe can mean to form the outline of).
'scottish town' becomes 'ayr' (town in Scotland).
'leader' going around 'ayr' is 'LAY READER'.
(Other definitions for lay reader that I've seen before include "Non-ordained person undertaking church duties" , "Unordained preacher" , "who carries out some services" , "licensee in church" , "volunteer for service?" .)