I think I have worked it out.
Created a table in my datawarehouse called 'table2', with columns -
id - int
date - datetime
time - time(7)
The in my SSIS Data Flow Task I have a "Data Conversion" task inbetween my source and destination.
I've then added the input colum of "planned_start_date" twice, one with an output alias of "date" and one of "time" with the datatype of database date and database timestamp respectively and it appears to do what I want it to.