Horse reference: mystery-colour jumper

This beautiful gelding showed up at a local show a few years ago. Don't he and his rider make a lovely pair? I think they placed quite highly too, although he was quite excitable!

Mystery jumper genetics: I'm still a horse colour amateur and I can't work out what this boy's colour is! His mane and tail being obviously darker, I compared him to some photos of red dun (diluted bay) horses. I don't have my own photo to share but they are much redder - almost like a liver chestnut with a dorsal stripe. Plus, it's hard to tell from my ringside photos, but he doesn't seem to have any dun factors or primitive characteristics. 

I pulled up the Guide to Horse Colours by Majnouna and looked through for horses roughly his colour with dark manes and tails. The closest match I could spot was amber champagne, but again a quick search for horses that colour brings up a lot who don't look anything like our boy here. In desperation I wondered if he was some sort of colour-going-grey, but it was really a desperate guess and is wrong too!

I have no idea what colour to call him! Is he just some sort of obvious chestnut I'm overlooking? But then he has such dusky bits and such rich bits in his coat, and that curious dark mane and tail, and complete lack of dark points. He's a mystery horse! Any suggestions very much appreciated in the comments.

As always, I would love it if you used my reference photos for horsey artwork. All I ask is that you link back to the blog if you share your work online! If the horse/rider in the photos is yours/you and you would like them removed, please let me know - otherwise feel free to use them yourself if you would like. Thank you :)