Fiesta Mode Door Sticky/Stuck

[megzaz]

For a couple of weeks I've been trying to solve an issue with my heating vent control. Beginning to lose hope it can be fixed without full removal of the dash. 

Car is a Fiesta Zetec mk7 (2016) with manual controls for the air vent mode (defrost / face / feet) i.e. without climate control.

A few weeks ago the dial appeared to come loose with the vents stuck on face mode. Investigating that by deconstructing the control panel on the dash, I found the cable had bent near the control dial. It eventually snapped as I went about removing it. I bought and fitted a replacement cable (Heater Control Cable, RHD, part no. 1619364) but I think the problem with the cable was a symptom of something else going on.

Going in behind the glove compartment, I cleaned up all the moving parts on the mode door actuator, adding some silicon to get it moving freely. The actuator seems to be in working order and with a gentle nudge I can get full motion from the control dial and actuator, rotating round from face to defrost. But without physically moving the actuator by hand (trying to use just the control dial) everything seems to get stuck, leaving the vents stuck again, either on defrost or face (the two extremes on the dial).

I'm suspecting there's something causing the mode door itself to stick. I've seen others post about Focus' mode doors getting foam stuck / having some rubber melt to cause similar issues. Trouble is I haven't a clue how to get visibility on the mode door to do anything further.

Can the mode door be accessed through the dash / control panels? Has anyone resolved this issue before?