Is there anyway to auto save when invoicing as I have lost so many half completed invoices as the program times out and doesn't auto backup ?

I've got two options you may wish to consider, marcel6.

You may utilize the QuickBooks Online Desktop app, which lets you stay logged in for an unlimited period. You can download it to the following link: Get QuickBooks Mac & Windows Apps, powered by QuickBooks Online.

Also, you can adjust the time required to be signed out for inactivity in QBO. Here's how:

1. Go to the Settings icon and choose Accounts and Settings.
2. Select the Advanced tab.
3. Click the Pencil icon located in the Other preferences section.
4. Select the drop-down next to Sign me out if inactive and choose the preferred amount of time. 
5. Click Save then Done.

For further insights into this, please check out this article: Change the timeout duration in QuickBooks Online

I'll be here to lend you a helping hand if you have other concerns.