Hi Faz,
I joined this forum solely because no-one to my surprise identified the spider mite problem that is so established on your plant. (with all due respect to the one member who suggested that it might be spider mites) This is a 'very' advanced infestation as recognized by the damage. The 'cinnamon' colour that is wiping off is the actual mites themselves. The damage to the leaf is left behind. I am aware that the thread is a few years old at this point and hoping that you were able to resolve the problem and that the plant is still with you.
Although I am a new member I have been growing for nearly 15 years and have a collection predominately of species (mostly paphs and asian cymbidiums) - but 50% of my plants are diversified and include nearly all genera. I haven't counted but I am over 500 and under 1,000 plants and they are grown in a greenhouse conservatory. I only add this to aid in my credibility -again- I am a new member.
Spider mites are immune to insecticides and cannot be seen without higher-powered magnification and are therefore impossible to identify unless you are familiar with their presence.
to kill spider mites -into 1L water sprayer- mix 30ml Hydrogen Peroxide (3%-H2-O2) ~ and 30ml 70% Isopropyl (rubbing) alcohol ~ and 5ml soap (dishwashing SOAP - IVORY suggested - DO NOT USE DETERGENT)
It's a contact killer so is required to be applied every 2 weeks for a couple months to kill generations (likely overkill
but better to be safe. Spray all leaf surfaces and make sure you get em all. A single application will kill adults and juveniles but will leave the eggs unaffected.
I've tried numerous treatments for spidermites on my collection until I discovered this magic-solution.
Previous research: Neem oil was my first choice and on application it killed -probably 25%- of my collection (I think in hindsight, suffocating the roots - works on plants but not orchids planted in open medium)
Hope this helps, Faz - and too hope this thread helps others faced first-time-with this nasty little (invisible-to-the-naked-eye) @#@%^*% PEST!!!