Hi,
Is is possible to help protect the doors with a spray tube and nozzle without affecting the the glass and other components.

Mel.

Think the best way would be to remove the door cards and keep the windows in the closed position then carefully spray with dinitrol or similar, avoid covering the electrics. though I have never seen a FL2 with rusty doors ....YET? 2013 FL2 XS.
Defender 90 300 TDi.
Defender 90 300 TDi CSW.
1964 MGB Roadster.
1944 Willys MB "Jeep" with bullet holes. (gone)
17 hand Irish Drought Thoroughbred (mostly lame)
Nagging Old Boiler.

Mahatma Gandhi said if there is an Idiot in power those who elected him are well represented

only doors that have been replaced due to accident are susceptible to rusting as they were not factory build painted.

Inside of door.

Click image to enlarge

I think the OP means where the inner and outer door join.

In New Defender LR spray the inner void with a wax, to prevent moisture gathering. Not sure they did that in the FL2 ?

I thought that has been standard on UK spec cars for years. Maybe not ? Jules

I was thinkig of removing the bottom door trim and injecting Dinitrol ML through the holes there but do not want to risk spraying everything. Perhaps it is better just leave it, on a powerful uk video when he removed the lower trim he hosed through the holes to remove the build up of crud, so I wanted to know if it is safe or not ? your thoughts please.

Mel.