To import the Mighty Deals orders do the following:

Select the Import Orders dialog (Down arrow icon or File->Import and Export->Import Orders menu option).

1 Click on the Add button to create a new OSOP import type (select the Other Shopping Carts, CSV format (OSOP Format) choice)
2 Select the CSV order file exported from Mighty Deals
3 Change the Date Format (in the OSOP options) to DD/MM/YYYY HH:MM:SS
4 Tick Use OSOP compatible header for order import file
5 Copy (and Paste) the following header line into the header box

Item ID,Order ID,Order date,Checkout date,Item title,Item title2,Item total,Total P&P,Custom:Entered val. 10,Invoice Firstname,Invoice Lastname,Invoice Address line 1,Invoice Address line 2,Invoice Address line 3,Invoice Postcode,Invoice Telephone,Invoice Email,Delivery Instructions,SKU,Dispatch date,Tracking ID

6 Tick Mark all imported orders as Paid
7 Click OK
8 Import the orders.