PGW

Thanks for all the useful comments and suggestions regarding my original question.  
From the sensible people I learned about the Hill Hold feature, this is the solution.
My car did not have this, that was the reason for it rolling back.  I exchanged cars with the dealer for one which had Hill Hold - the replacement one is absolutely perfect.  If the engine stop start function is activated the car will hold itself on a hill long enough to accelerate and drive away.  It is just as I expected it to work, and similar to automatic cars with the normal torque converter type gearbox, so the handbrake is not necessary.
If anyone wants to buy a DSG Skoda Superb I would definately advise to get one with Hiil Hold, in my opinion it is a 'must have' option.    
Thanks to Andrew Pengelley at Specialist Car Skoda Aberdeen for allowing me to exchange the car I bought, and sourcing a similar spec model for me with the addition of Hill Hold.  Great customer service, recommended as a dealer.