Custom Field / Default Value / Check Boxes

Hi,

I have a custom field that I’ve called ‘Services Offered’, I have set the field Type to CheckBox.
The default values are:

NHS,Private,Local Collection/Delivery,Freepost,International Delivery,Training Facilities

So far all looks and works great, and users can enter multiple answers/checkboxes fine.

But, I don’t know the correct way to enter these multiple answers into my csv file. I must have tried 30 different combinations but still no ticks in the boxes.
I’ve found that I can get one value ticked if I only enter one value, but I need to find the correct way to get more than one box ticked.

Anyone got any ideas?