Thank you for the quick reply and excellent solution my friend.
The mains power management was already off. I changed it to on and now it seems to have fixed the issue (the laptop is still slightly slow, but I believe this to be related to the errors flooding my syslog).
Now the iwconfig is:
Out of interest, is there an explanation as to why this happens without power management?
lo no wireless extensions.
eth1 IEEE 802.11abg ESSID:"my_ssid"
Mode:Managed Frequency:2.442 GHz Access Point: **:**:**:**:**:**
Retry long limit:7 RTS thr:off Fragment thr:off
eth0 no wireless extensions.