SBG 900 seems to time out too fast when I'm making changes to set

I have recently needed to open up a couple of ports on my SBG900 .

Whilst the ports and firewall settings are now working fine, I had a heck of a job setting them up.

It seemed as though unless I went into the modem like a Mission Impossible IT ninja and made all the configuration changes in less than about 10 seconds, every time I hit apply, I'd been timed out and returned to the log-in page.

If i broke the speed barrier, it was happy and applied the new port configurations.

According to my ISP there's no way to extend this window of opportunity - any ideas?