I went here last week. As they had an open garden. Beautiful setting. Im more into buildings but the estate wasn't open this day. Only the gardens.
Open Garden entry fees:
Adults - $14
Concession - $10
Children - $5
National Trust members - Free

Open Garden and House entry fees:
(NOTE: House and garden are only available in May and August 2018)
Tickets:
Adult - $22
Con - $18
Child - $10
(Sorry, there are no 'House Only' tickets.)

Approximate cost: $14