Guys

Took car in and guess what?
No code and they could not replicate fault so I'm on watch and wait.
Funny enough it possibly happened again but this time I was at a traffic light on a hill - rolling 2m backwards was again scary and thank god there was no one behind.

They did replace a faulty hand brake switch that may have contributed but not sure how.

Anyway back to driving.
Overall I love the car the only gripes I have are:

# No auto fold on side mirrors - I live on a busy road and have lost a couple in the past
# Can't open the tailgate when I have a trailer or bike racks on
# 90kg tow ball weight restricts what I can tow - basically a lightweight camping trailer
# voice recognition hates my accent