Foreword: SCITT email forwarding will stop working on the 1/10/18. Please make sure you have changed over any accounts to your new email by then.
Login your old Angmering account by going to "mail.google.com".
Once you are in Gmail go to settings icon (Top right) and then click Settings again.
In the top menu bar click "forwarding and POP/IMAP".
Under the heading for "POP Download" click the check box marked "Enable POP for all mail"
Now logout and navigate to mail.google.com again. This time sign in with your DMAT SCITT account. Now go to the settings icon (Top right) and then click "Accounts" along the top.
Then put the details in for your angering SCITT account. Untick 'leave a copy of the retrieved message on the server' and tick 'always use SSL' and then add 'pop.mail.com' using port '995' if asked.