Addidional information for those that want to know.
I don't believe that this was a simple dump process. 'cos
a. The fuel flow was consistent and heavy until the flow was dispersed into spray as the a/c gathered speed on the runway.
b. On arrival at Singapore, maintenance crews decended onto the aircraft.
c. We did not make the next scheduled leg to Brunei instead passengers for Brunei left the a/c and we had to wait for the Brunei-Oz passengers to arive at Singapore.