Two things found in the loo, one blown (3,5)
I believe the answer is:
pan pipes
'two things found in the loo' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'one blown' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for pan pipes that I've seen before include "Wind instrument" , "divine instrument" , "Instruments" , "one making notes" , "Musical instrument made of reeds of different lengths" .)