Closing as I’ve solved, but leaving solution here for anyone else
Need to do the additional config for Lock as listed in this article:
var lock = new Auth0Lock(config.clientID, config.auth0Domain, {
//code omitted for brevity
configurationBaseUrl: config.clientConfigurationBaseUrl,
overrides: {
__tenant: config.auth0Tenant,
__token_issuer: 'YOUR_CUSTOM_DOMAIN'
},
//code omitted for brevity
});