Potentially I am looking at getting DDI's in a couple of other countries.

Primarily the US and also Australia... do you think it is best to find a SIP Trunk provider local to that country and rely on routing through the ISP t them, or is it better to find a provider in the UK (where I am) and then they will (presumably) have preferential optimised routing to drop off points in those countries?

Ideas on a postcard - also, which, if any, would you recommend?