Update: probably can see better with this image having tweak the colour and contrast.
My apologies for posting this stamp again. There is some new information. The postmark is fairly faint and I did not looked closely enough to uncover its potential. I initially failed to notice it is a "Gayah" and only in the last few days did I realise it is also prefix "A". The Gayah postmark (1886-1897) usually has a prefix "B" above the date which can be omitted in some stamps.Gayah "A" is apparently very rare. With this high resolution scan, I can confidently see GAYA(H) A 15 FE 1886. The day and month are in a different order as the month normally comes first. I have just seen my friend's clearer copy with the transposed date as well.
It seems very likely that the "A" prefix was in use earlier than the "B" from the dates seen. This variation in prefix has much in common with the very rare Elopura "A" and Kudat D2 "P" postmarks.