So the first version of the tuner was a dismal failure. Somehow i ended up with 300pF of stray capacitance floating around and, well, as you know, that is only ever going to screw things up. Now I am not sure that I have fixed that problem, But i have pulled back the copper pour on top and bottom around the RF path and that should reduce the stray capacitance, i have also used different relays and modified the design slightly. All things which should help.
The other main thing i have done is moved to the ESP32 rather than an arduino. The plan here is to be able to remote control the tuner over wifi thus allowing it to be placed at the feed point to the antenna. SWR and auto tuning will come later. First thing is to get this part actually working as a tuner.