Clutch fluid dark

Linga

Linga

Hi guys,
My clutch fluid is really dark and I'm only 1000km past a major service. I got advised to replace with motorex but would like to see if there is a problem first so as not to waste time. I'm worried that something is running hot down there. Any thoughts? The bike has done 20,000km.
Any help would be appreciated.
I'm also thinking of getting an Oberon slave cylinder.