We'll be parking there too.
It should take about 4 minutes.
The car park is behind the shopping centre on the other side of the road. (Steadfast Road)
Come out of the ground floor of the car park and walk around to TGI Fridays (you can see the awnings on googlemaps).
With TGI behind you cross the road towards Bentalls.
Turn left and keep walking for a few minutes.
Cross Back again when you see the Rotunda.
If you go to the shops first take the exit from the Bentalls Centre next to
Disney Store (DS will be on your right)
Continue up this road to its end. (Fife Road)
You will see the Rotunda across the road (slightly to your right)
(Hopefully this makes sense.)