BT Business Broadband MaxDSL upgrade

Hi all,

We have recently upgraded to 8Mb ADSL for our Business Broadband. Today
the adslguide speedtest is reporting 2.7 down and .7 up, which i
imagine means that we are currently in the 'training' section. Problem
is that whenever we try any consistent uploading (such as an ftp upload
to an external server) the speed shoots up to 80-ish KBper sec for about
10 seconds and then drops off altogether to nothing.

The router we have has been working great on the 2Mb service (A BT
Supplied Siemens sb5830 (rev b)), would there be an issue with the
router itself or just part of the regrade process and i just need to
ride it out?

Thanks in advance,

Dave