Many thanks once again for your responses. I am pretty sure it was an engine surge from what you have all described, and specifically from the links to the videos you gave me. There is another one of a Swiss Air flight experiencing an engine surge which also looks similar to what we experienced:
YouTube - Swiss Air A330, Having Engine Surge
Would it be normal procedure to shut down the engine following a surge? This definitely happened and it sounded as though the other engine was labouring.
gdiphil - your experience sounds very very similar to mine - did it make you nervous following this?
Thanks again.