A 200-seat restaurant was approved by Cotswold District Council in May and is due to open in autumn 2013.
Pleydell Smithyman director Paul Pleydell said a local group had raised some objections but he was working closely with planning officers and they "understand what we’re doing". Councillors and local supermarket Budgens said Fosseway could take business out of the town.
He added: "This has caught the local imagination but they [Fosseway] have been there a long time. Fosseway is a local family business, employs local people and is part of the local community and attracts people to the area to the benefit of everyone else."
When it was given permission in 1989, the centre, owned by Tim Godwin, was allowed to sell whatever it liked in 362 square metres of space, but the rest of the building was restricted to garden centre products.
Pleydell added: "We’re trying to pin down and make it more defined at the moment. That’s not uncommon. We’re finding that with the majority of planning applications we are having to define what we mean with garden centres and product definition. It can mean different things to different people."
Fosseway wants to sell "core garden products" anywhere on the site and Christmas products for four months a year.