Although my UBR seems to have been upgraded to take 1mbps uploads, I am still getting low upload speed (not that it's an issue I don't do a great deal of uploading apart from source code files to CVS.

This has been going on for as long as the modem has been reporting 1mbps upload speed.
Modem upload stats are:
Upstream Lock : Locked
Upstream Channel ID : 1
Upstream Frequency : 25800000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 35.5 dBmV
Upstream Mini-Slot Size : 2
Any observations?