The channel that I believe was breached by Gneisenau and Shnarchorst in 1942 from Brest to Wilhelsmhaven, was crossed with minority of british resistance proves that nothing could stop Germans from passing the straight of Dover at the time they did it. Somewhat a disapointment to royal navy wasn't it ?
Braking through the Channel
One breakout in six years does not constitute naval control. Admittedly though, kudos to the Kriegsmarine, it was a ballsy move, we were expecting them to make a break at night, not in the middle of the day. Caught completely off guard.
Several dozen uboats, and eboats were not so lucky in the channel though.
Furthermore, honestly, it was better for the Royal Navy and Britain as a whole for those two ships NOT to be in France, where they could threaten Atlantic convoys, but to be cooped up safely protecting against an imaginary invasion of Norway.