timetable
You'll be wanting the one that goes to Captains Rd and Frogston Rd. It says Princess Gate on the timetable though..
If i remember correctly, there's a bus stop about 150yrds from the entrance to the Garden Centre, thats where you turn into the Stables.
I'll warn you though, it aint the quickest bus to get.
Just ask the driver when you get on if thats where it goes, and keep an eye out for getting off, as it's easily missed.