The SurePet Feeder uses a 802.15.4 based protocol called MiWi P2P. This is a protocol that is made by Microchip.

The following link shows someone who has captured some of the P2P frames and has mapped them to a spec:

https://github.com/alextoft/sureflap/issues/8#issuecomment-698580972

From the following link, it appears that the beacon is transmitted on channel 15:

https://github.com/Koenkk/zigbee2mqtt/issues/3261#issue-591745054