W7500 Update from HTTP

Is it possible to download a new bin file from an HTTP socket and then replace the existing firmware with that? ie can the device update its own code?

Is there any documentation on how the flash ram can be used from within code that I assume is running from the flash?

Normally, you can use two application simultaneously, One as a boot and the other as an Application.
WIZ750SR repository on github shows how you can implement it with W7500P.
Please refer to GitHub - Wiznet/WIZ750SR: WIZnet Serial to Ethernet(S2E) module based on W7500 chip, WIZ107/108SR S2E compatible device