Hi - anyone has experience of feeling light front wheel steering as if the wheels fail to get traction and want to wander off line? If get this when accelerating slightly on slight uphills typically in gears 4, 5 or 6.  It's quite disconcerting and garage only able to offer wheel tracking and no other suggestions. Some feedback if others have had this issue would be appreciated. Tyre pressures all ok and wheel tracking ok. Many thanks.

Vehicle is 16 registration, X1, S-line.

You could find somewhere that has 4 wheel laser alignment and knows how to interpret the readings.

It depends on loads carried and normal driving behaviour but generally the readings should be in between a set of min-max ranges. 
With a rear wheel drive car that is displaying this type of symptom, normally the track would be statically set to toe-in and when accelerating it would naturally tend to try to toe-out.
So, it may be worth setting the tracking to maximum toe-in for that particular model (with appropriate load settings, etc) and see if that makes any difference.

I would also look at tyres (pressures, rating, sizes, etc) to ensure that everything is where it should be. Check for uneven tyre wear which could indicate a suspension/steering component that is damaged or excessively worn.