Sorry to bring this back up - I don't often end up on here (sold my own GTI a few years back) but when ever my girlfriends car has an issue I find here very useful. It is a mk3 8v gti 135000 on the clock.
I have been watching the oil temps on it and worrying they run high. On a 85 mph run she gets up to 104 - 108 depedning on external temps (sub zero on way to alps to ski barely over 100, hot run the other night 108 tops with speeds heading north a bit!)
Glad to here this doesnt appear to be unusual. The oil cooler works as when you ease of the temp drops quite quickly. Replaced the oil breather hoses the other day and that certainly made a difference as before the same 85 plus peaked over 110 on occasion.
Car runs fine except a 5k rpm issues (suspected hal sensor) and averages 35mpg on fast A road driving commute. Glad to hear it appears normal!