Vanda Discoloration Potential infection?

[UK Orchid lover]

I have had this vanda for about 10 years.

min temp= 19C in winter, Max temp= 30C in summer (degrees C)

Grown in a normal British home grouped with many other orchids. No other orchids in my collection have these marks.

It started about a year ago at the bottom of the stem on the lowest leaves and has begun to climb the plant very slowly.

Could this be a temperature issue? Age? or infection?

It is a very large vanda (noID similar to the pachara type)

There are no bugs present after close inspection and the roots are very healthy.

PLease help me

[UK Orchid lover]

- the shiny parts on the leaves are where i attempted to use clear nail polish to prevent spreading of the dark dots. There is a white dot on one of the images aswell but that is a leaf scar from mechanical damage.

[estación seca]

I don't see anything beyond normal wear and tear. The dark areas along leaf margins may represent periods of high light after a long dimmer period. Note how the plant grew after they formed.

The pale mottled area may represent sun or heat damage, or nutrient deficiency.

Phyllosticta fungus occurs on the upper surfaces of leaves and tends to have diamond shaped spots.

Magnesium deficiency in Vandas may cause overall purple spotting, worse in cooler weather and with numbers proportional to deficiency. How are you fertilizing?

[UK Orchid lover]

Ah thank you for your advice, and yes I am not consistent with fertiliser. I will defiantly get onto that now as it is most likely the issue it seems.