Messed about, like Hogwarts Harry? (8)
I believe the answer is:
pottered
'messed about' is the definition.
Although both the answer and definition are past participle verbs, I can't see how they can define each other.
'hogwarts harry?' is the wordplay.
I cannot quite understand how this works, but
'harry?' could be 'potter' (Harry Potter) and 'potter' is located in the answer.
The remaining letters 'ed' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'like' is the link.
Can you help me to learn more?
(Other definitions for pottered that I've seen before include "Did nothing very much" , "Busied oneself in an idle manner." .)