Yes, we started at Tower bridge. I'll dig out the route for you if you want. We went over the Ditchling Beacon down into Brighton and along the coast to Newhaven.
Here you go https://www.strava.com/activities/1159842738
You can see we made an error just outside Brighton and could of taken a more direct route into Brighton. You can alter the route to suit you. The route right along the front of the cliff is nice(except we have terrible rain from Brighton to Newhaven)
The route finishes a few yards from the ferry entrance.
Are you staying overnight in Newhaven before catching ferry? You will know there are only a few crossing per day . The afternoon ferry gets you into Dieppe very late. It makes the first day an early start and you must keep the pace up(12mph). I know it doesn't sound alot, but with novices it's plenty.
Once in Dieppe the route Becomes alot more relaxing in pace, there is no time penalty issues with catching ferries
Cheers Andy - I appreciate that . I'll take a good look at your route.
We're planning on catching the 5:30pm ferry after reaching Newhaven. The first one the next day won't get us into Dieppe until 2pm so need to get the 5:30 one. I'm assuming an average of 12mph which will help dictate the start point/time in London. Two of us will be cycling Chester to London over two days beforehand, so the slower pace to Paris will be welcome
The French side of the route I'm planning looks really quite nice with plenty of off-road cycle paths (mainly along the Avenue Verte) and enters Paris from the West along wooded paths.