I do have a great recommendation: Last September we visited D-Day sites for two days with a company called Battlebus. Operating from Bayeux and widely praised, the company has six or seven English-speaking (perhaps all British) guides.
The six of us asked for the itinerary to be constructed on the framework of the company's "American Experience" tour. Our guide Alan, a military history buff since the age of 7, was super. His specialty, since he long ago had realized he couldn't "know everything," was the American and German roles in the start of the battle of Normandy. In between presentations - overviews interwoven with intimate accounts collected from veterans on-site - we peppered him with questions.
A pause of a few seconds and then he delivered effortless, in-depth answers, lasting as long as five minutes each! We visited major sites and sites where obscure engagements took place, where the commentary zoomed in on soldiers by name. Not only what they were doing, but also what they were thinking.
Amazing stories of heroism, villainy, even love. A very moving learning experience. Well worth it while you are in Normandy.
Dave