You shouldn't have any worries at all providing the price is right.
High milage is not that important, you can afterall quite easily change the mechanical bits and pieces quite easily and if you've been runnig and older car, I'd assume your hands on and able to take care of that.
Much more important is the condition of the body and interior, these cannot easily be fixed on a DIY basis.
Have a look on tdi club forums and you'll see some cars with silly milages on them, still going strong, think there is one with in excess of 350k on it with all the original parts!
The car your looking at should have the old 110hp rotary pump engine which is bullet proof.
There are two schools of thought with milage and mine, being always to take the high miler means that you know the car is good, has been good and has been looked after. I'd be weary of an older low milage car as it has not been excercised properly and in all honesty interally, the engine would probably be in worse condition than the regularly excerised high miler. The best bit is you save yourself ???'s going for a high miler.
Since giving up having a company car, all my own vehicles were purchased just out of lease with quite high miles BUT with dealer stamps all the way through, they have all gone on to do in excess of 150k with no real problems at all. Gone are the days when engines expire at or before 100k, your Grandfather or Father may have told you stories about their old marinas blowing up at 70k and you may believe them, but times have moved on.
In fact, these days most cars go to the breakers because they are falling apart not because the engines have failed. If a car gets to that age where it does start falling apart without being smashed up it's quite lucky. As for falling apart, VW's generally don't do they ?
Have a look on the roads, you still see plenty of MK2 Golfs from the mid to late 80's, how many old Astra's or Escorts do you see from the same era, virtually none.
Like I say, providing the price is right, go for it.
P.S. The old Mans '99 Passat with the same 110hp lump is still going strong at 148k....