is it a clutch or other problem

[medni]

hi my revs seem to be high after changing gears and coming back down to their normal level after a while but in 5th gear even at 70 they seem to be nearer the 4 mark
its a e34 520 1990
i know the clutch is nearing its end and also oil service should be coming up i have 2 green lights still on
could it be the car needs service
or is it the clutch
i mean is that a genuine symptom for the clutch going revs being high after change
any info would be appreciated
ps how much should i be looking at for a clutch change at an independent in sterling