Hendrix Martin, Brenton Crombie and Thomas Schultz pleaded guilty to Yummy Box restaurant robbery

Three men have admitted to a terrifying restaurant robbery – where a staff member was hit with a hammer and repeatedly kicked – alongside their alleged fourth accomplice.

Three men have admitted their role in a violent robbery of the Yummy Box restaurant where a staff member was struck with a hammer and repeatedly kicked.

Hendrix James Martin, 32, and Brenton Paul Crombie, 23, pleaded guilty in the Adelaide Magistrates on Wednesday to theft using force and two counts of assault, stemming from the Park Holme restaurant attack in October last year.

Martin, of Christies Downs, also pleaded guilty to serious criminal trespass.

A third man involved in the robbery, Thomas William Schultz, 22, pleaded guilty in July to theft using force, serious criminal trespass and two counts of assault.

Counsel for the men’s co-accused Isabell Grant told the court they were seeking an adjournment to consider a possible resolution offer put to them by prosecution.

After her appearance in June, the 19-year-old woman hurtled out the front doors of court at top speed.

However, on Wednesday she left court in a far less frantic fashion, looking composed and flagged by supporters.

Isabell Grant making her flying exit from court in June. Picture: NCA NewsWire

Ms Grant was far more composed leaving court on Wednesday. Photo: Lucy Rutherford

Ms Grant, of Keswick, is yet to plead to aggravated counts of theft, assault and serious criminal trespass.

CCTV footage of the incident shows a woman and two men getting out of a Toyota Landcruiser and attempt to drag another man from a nearby Mercedes.

It also shows them enter the store, strike one staff member over the head with a hammer and repeatedly kick another even after they had fallen to the ground.

Brenton Crombie, Hendrix Martin and Thomas Schultz pleaded guilty to the Yummy Box robbery.

Police allege the group stole personal items, including a wallet and car keys, belonging to both staff and to the owner of the Mercedes before fleeing the scene.

In the Adelaide Magistrates Court on Wednesday, Magistrate Simon Smart adjourned Ms Grant’s charges until later this month.

Crombie, of Coober Pedy, and Martin were committed to the District Court for arraignment next month, while Schultz, of Port Augusta, will appear in the District Court later this month.