How can I export individual submissions as a .txt file

I want individual submissions exportable as plain text, with line space between so that they are mroe easily machine readable (eg for eprint and vba use)

is this possible?

Unfortunately, this is not possible. You can only generate the single submission as PDF and you can generate the entire submissions as CSV or Excel:

http://www.jotform.com/help/44-How-to-Export-Form-Data-to-Excel