Lochnagar is in Langmeil Estate, Tanunda.
Turn off the main street at the BP On The Run service station into Para Road. Follow this until it turns left into Langmeil Road. Turn left into the Langmeil Estate and Paradale Drive. Carry on around the corners and Lochnagar is about 400m - No 22 - on the left.
Alternatively follow your satnav and look for the house on a double block with the gardens once it says you have arrived.