Hi @Simonwarner89,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
While it would likely be possible to repair the door, it isn't really practical when you consider the difficulty and cost of repairing the door, with the difficulty and cost of installing a new hollow core door like this 720 x 2040 x 35mm Internal Door.
To repair it, you would need to cut out the damaged lock block, cut a piece of timber to replace it, install it, cut thin MDF to replace the veneer on the door, fix and glue it all back together, patch any seams between the new MDF and old then redrill the holes for the lock, and reinstall the hardware before painting.
If you replace the door, you will just need to remove and reinstall the hinges and doorknob to the new door and maybe trim the door a little bit. You could use the old door as a template for the new one and use this Ryobi Wood And Metal Door Lock Kit to make the lock installation simple.
You might like to check out How To Hang a Door and How To Install A Door Lock for some guidance on the process.
If you weren't interested in doing it yourself, you might also consider our Door Installation service.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
