Hi,
This can easily turn into one of these "what if threads", but please allow me a few comments. Without total air supremacy over the beachhead on 6 June 1944 those 43,000 tanks would never have come ashore. RAF BC contributed to the attainment of that.
The V-1 sites were being constructed from the end of 1943 and would have been ready to fire before the invasion - against the ports in Southern England, had it not been for the effort of BC.
bregds
SES
www.gyges.dk