Thanks all- I've gone with your suggestion, MC, looks good.
However I forgot to mention, even when Outlook is open, I still have to click on Send/ Receive, even though I have selected in Tools- Options- Mail Set-up- Send/Receive- in both Setting for All Group Accounts, and When Outlook is Offline, to schedule an automatic send/ receive every 15 minutes.
Unfortunately, I still have to manually press Send/ Receive to activate emails.
Any thoughts?