Any idea what kind of engine was put in at that 147k mile point - new, rebuilt or just used?
And if you can find the maintenance records for other fluids, suspension etc, that'd be nice. However, if you feel like everything was tight when you checked it out, no worries.
Those short oil change intervals are beneficial to ward off any ill effects of oil consumption.
Regarding oil consumption, you might have read about those issues with these engines. This is what I'd do:
1. Check the oil level in the dipstick when cold and compare it to the last oil change mileage.Too high/too[ low
2. Be present to start the car cold if your schedule allows. If you hear any ticking, tapping or knocking, I'd consider walking away.
Otherwise, even for a base model M45, the price isn't bad. If it's loaded, even better. I wouldn't shy away based on the odometer alone.