Login to your control panel at https://cp.domaincheck.co.uk/cp
In the subscription drop-box at the top of the screen, select your Plesk Domain subscription.
Click on Mail
Click Mail Settings
Select the domain you want as catch all and click on the Mail for Non-Existent User
Tick on Forward to address, add the email address you want your emails forward to, this will be on you already have set up in control panel
Click on OK