Had some spare 92mm fan grills and was inspired by
Soundsgoodtome. Removing the original grill made a bigger difference that I was expecting, basically went a tier up in terms of sound-stage and clarity over the whole spectrum.
The HE-560 are really held back by the original grill, too restrictive, I tested this after I took them off by blowing air at a constant rate over the back of my hand and slid the grill over the air stream, the air restriction is stark. Highly recommend to mod the HE-560, not very difficult either.
Many thanks to this thread for upgrading my headphones