The original Post Office at Whitminster closed about 18 months ago.
Highfield managing director Joan Greenway said: "We were approached about 9 months ago by Whitminster Parish Council, which was disappointed at the loss of the service. Although it has been a challenge to fit in the service with the running of the garden centre, we are proud to once again offer the most essential Post Office services — not only to the residents of Whitminster but also to the many hundreds of thousands of customers who visit us each year."
The Post Office Local will operate from the main information point at the garden centre with Joan's son, Tim, as the new sub-postmaster heading a team of staff ready to offer a range of Post Office products and services.
The Post Office Network Change Programme was a UK government-led initiative to "modernise and reshape" the network.
About 2,500 branches were closed in the UK during an 18-month period from October 2007.
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