Thanks for the suggestions folks.
BTW, I'm in the camp that says an invasion would not have succeeded. Most of the transport shipping consisted of canal barges with odd bits of weaponry welded to them. They were totally unsuitable for the open sea and many would have capsized, been swamped, broken down etc without any help from the British.
Also, air cover notwithstanding, enough RN ships would have got through to wreak havoc against the aramada.
Dowding would not have kept the other fighter Groups out of the fray either.
If the boats had started moving everything would have been flung against them.
All IMHO.