Been having a bit of fun and games with ADSL since moving house. Have
had the issue checked out, and other than some extra unused wiring in
the house, which the Telstra tech disconnected, there are no known
issues on the line.  The Telstra tech's test unit can sync at nearly
4Mbps, and a Bigpond router (not sure what brand these are) will sync at
4.2 Mbps.   However, I haven't had so much luck.

When it comes to ADSL modems, it's the chipset that matters, not the brand. If you're that far away from the exchange, definitely try and find something with a broadcom chipset, and avoid trendchip chipsets at all costs.