Ken,
I must admit I don't understand ANYONE thinking Paris is a one day venture. Please find some other source for advice on seeing Paris. Your whole week could be filled up just seeing a small part of what Paris has to offer. The suggestion to visit Buckingham palace and going straight to Paris via the Eurostar train (not usually called the Chunnel in England or France) is a good one. However, the time spent in moving from England to France will use up a good part of a day out of your holiday time. Would your wife be amenable to seeing Buckingham Palace on another trip and flying straight to France? If so, you will see an even more impressive palace at Versailles, a day trip from Paris. You wouldn't need to spend so much of your week moving from country to country.
Re the Normandy beaches.....Bayeux (a good spot to begin your tour of them) is 170 miles from Paris. The train to there, from Paris, takes over 2 hours one way, so with an early train out of Paris, and a late train back, it is doable in one day, but not the best option IMO. Half the day will be spent on the train. You could take a guided tour of the historical sites from one of several very good companies. They aren't cheap, IMO, but well reviewed by just about everyone who has taken them. They would pick you up and drop you off at the Bayeux train station.
Your 7-8 days....do they include your arrival and departure days or just the days on the ground sightseeing? Be sure to allow for those two days. If you actually have 7-8 full days there, then you might fit in 2-3 days in another city besides Paris. Just be sure to allow for time involved in changing locations.
If you count nights in a place you may have a better idea of your time. Two nights in a city=one full day. How does this sound to you:
Day 1, arrive London, get to hotel and check in. Tour Buckingham Palace if you arrive early enough in the day. If not, see it first thing on day 2. Sleep London.
Day 2, Buckingham Palace first thing, then Eurostar to Paris. Or Eurostar to Paris first thing. Sleep Paris after some sightseeing. Maybe dinner on the Eiffel Tower if you have reservations for that evening. Allow plenty of time to get there from London. Or do the Eiffel Tower the next day.
Days3-5 Paris. One of these days will be about 3/4 taken up with Versailles. Sleep Paris
Day 6 Train to Bruges or Amsterdam Sleep in whichever one of these you choose. (I suggest Bruges. Amsterdam needs more time than you have.) (fyi, Bruges is 184 miles from Paris)
Day 7 Bruges, then move to Brussels for overnight stay before flight home the next day from Brussels.
Day 8 Fly home.
Better option (IMO)...Fly to Paris. Stay every night in Paris. Day trips from there: 1. Versailles, 2. all day trip to Normandy beaches as explained above (possibly), 3. Reims for champagne tasting tour and visit to cathedral there. These require no moving to another hotel. You will find way more to do and see in Paris (and its outskirts) with the rest of the time there than you can fit in. Check any guidebook for a suggestion of things to see and do in Paris. It has an abundance of choices. And to me it is one of the most romantic cities in the world! Perfect for an anniversary!
Whatever you decide, I strongly suggest you don't try to go to so many cities within one week. Please don't underestimate the time and effort you will spend moving from city to city and country to country. With just one week, give yourself time to wander or to sit back with an aperitif at a cafe and watch Paris go by.
Enjoy!