Factory Reset PowerSwitch S5248F-ON

We have 2 PowerSwitch S5248F-ON that were set up for us by a 3rd party a while back to be on either end of a fibre p2p.

we want to use them for something else but dont have the logins and so we want to factory reset them.

I dont seem to be able to download the OS10 to reinstall and only have access the the onie-rescue which limits us.

Im new to the dell and so learning on the go.

Does anyone have info on how i can sort this so i can configure these from the beginning