There is a simple work around.

Add a viapoint at, or close to, your marker.

Click on that viapoint and select "Write note"

Write whatever reminder you wish eg  campground on right.

This should show up as a TBT direection in the same way as "Turn left" would.

However......

You'll need to test this with your device.  

There is the possibility (I suspect) that my note may be overpowered by an "official" instruction (so try to place the viapoints on straight sections).

I have been using this feature for quite a while and love it. My device allows me to scroll ahead in the TBT directions to act as a physical reminder of what's down the road. 

c.t does try to include the markers that you've plotted in the TCX course. If it's not showing for you, please do link to a journey where it's not working and I can take a look. (You'll need to make sure both the journey and the markers are public not private - I can't see them if they're private!)

Many thanks both. I'll try that workaround, if it works, that's good enough for me. In the meantime, here's a link Richard. I believe it's all publicly visible.

https://cycle.travel/map/journey/540849

I’ve had a bit of a poke around and I can’t see any reason why the markers wouldn’t be showing – they’re all being included in the TCX course file. (Just checking – it is a TCX course and not a TCX activity you’re exporting? Activities don’t include markers or directions.)

If you could email me the TCX file you’re getting ([email protected]) I can take a look, just in case what you’re seeing isn’t what I get. But I think it’s probably going to be a question for Lezyne to answer.

Well the workaround did indeed work, thank you HobbesOnTour. I agree it's likely a Lezyne issue Richard, I can send you the file if you want it but I'm more than happy I can mark up points of interest/segments which is all I need. Thanks.