Ray, what is the source of your EV route?

Is it this one from the CT Route Guides? 

Are you doing this on the app (Android/IOS) or a computer (Operating System)?

The route is about 1300km which shouldn't be too long for Garmin, but it does use a lot of Viapoints - approx 200 - which may cause a problem for Garmin. 

I'm guessing that a quick fix would be to start with a blank map, enter the start & end points, select 'Routes' and CT should calculate the same route (Route Guides were put together before 'Routes' was an option).

By the by, on a long route like that, I'm not averse to letting CT choose the route - even if it's not 'official'. 

Hi HobbesonTour - you link to the route I am trying to download.  I will experiment with your suggestion of the blank map and compare the result to the 'official' EV4 route (would prefer to use the route signposts as backup for the Garmin). Ironically I only want a relatively small section of the route around Brittany, not the whole thing, but I can't edit it without first uploading....unless you know another way to download just sections of a route 😁

Ray, have you checked out the help?

Check out the Advanced Features, specifically Route Tools & More. The 'Delete Before' & 'Delete After' features will be useful for your needs. 

The steps should be (based on what you have written)

Open the route

Edit the route to your heart's desire. 

Save the route.

After that, depending on whether your Garmin Connect account is connected to your CT account, the steps will be different. You can read more here.

Sorted 😁.  Thanks for the tips HobbesOnTour.  Can now build routes anywhere 😁.  Looks a really good tool once you learn the basics - really like the 'divide into x days' tool and the hotels tool.  Should make our pedalling around Brittany much simpler.  FYI, it did post the full route into my Garmin Connect account...just took a bit of time - no spinning wheel to tell me it was uploading.  Uploads as expected with a bit of patience.