Slow upload to Apple. Traceroute ****s at 2nd hop

[Networking]

We've been using iTunes Producer to send files to iTunes. The problem is, the uploads are painfully slow and peppered with timeouts. We have an iMac connected (by ethernet) to a BT router. Google, the BBC, Slashdot, and a host of other sites that I thought of off the top of my head pinged fine...