I think Vont Fhood had it in a nutshell. Panel fell off, aircraft returned, 45 minutes later departed again? Panel would no doubt be fibre glass or small flat light alloy metal, fluttering down harmlessly like a sycamore seed- probably stuck up in a tree with a disgruntled crow eyeing it suspiciously. Drama over. No need to take up R & N with such a nonentity of an enquiry. What more is there to say? What was expected?