I can confirm that there was definitely one or more prop-a/c landing/taking off at LHR at around 2am on September 1. My ears are not that bad yet to mishear tinnitus for a prop a/c.
I was waiting for my lift home after my bus from LTN to LHR (the EI 184 ex-DUB diversion) outside T1, so it's near 27L...
:-)
S.