The settings stay correct and I can view and click save the tunnel connects successfully eg.
interface: wg0
public key: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
private key: (hidden)
listening port: 51820
peer: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
endpoint: xx.xx.xx.xx:51820
allowed ips: 0.0.0.0/0
latest handshake: 21 seconds ago
transfer: 124 B received, 180 B sent
persistent keepalive: every 25 seconds