E-mails and redirect

[#1]

If I set up a redirect for one of my Plusnet mailboxes will
1) Any e-mails arriving in that mailbox be automatically sent to the redirect address and :-
2) Will copies remain in the Plusnet mailbox until requested

[#2]

Mailboxes and redirects are mutually exclusive. You either have a mailbox *or* a redirect, never both. A redirect doesn't store email anywhere, it simply relays it to the chosen destination.