Simplest, but slightly longer, route is to keep going on the B3081 until you get to Horton (6 or 7 miles) and then turn left. It's more or less straight on all the way to the ground (another 2 miles or so), with just one slight left turn at a fork for Petersham Lane. Ground is on the left hand side. I can't remember any specific landmarks at the turn. There are other shorter routes in, but I learned them by trial and error when we played at Holt regularly.

On Google Maps you need to head for reference 50.841774,-1.973505

From Ashley Heath RoundaboutRingwood, Dorset, UK

1. Head northwest on Ashley Heath Roundabout toward Ringwood Rd 210 ft
2. Continue straight onto Horton Rd 1.9 mi
3. Continue on Ringwood Rd 1.6 mi
4. Continue on Horton Rd 0.8 mi
5. Continue on Clump Hill 2.5 mi
6. Turn left 0.7 mi
7. Slight left toward Petersham Ln 1.0 mi
8. Slight right at Petersham Ln 0.4 mi

Petersham Ln