Since upgrading Vigor AP-900 firmware to v1.1.8 (25 May) the security settings for the 2.4 GHz wifi are not showing satisfactorily. Security does not appear to be compromised but this is a worrying issue and prevents any further wifi security change to be made - has anyone else observed this?

I don't see that on an AP900 that I have access to that's on 1.1.8 firmware - how many SSIDs are set up on yours and are there any spaces or special characters in the SSID names?
The one I'm looking at has two SSIDs with no spaces or special characters in them

I also have two SSIDs, no special characters or spaces, both 11g + 11n, AES on one, AES + TKIP and isolated member on the second - however I cannot confirm this because all this info is now blanked out and mode drop-down has nothing there on appropriate web page.An error appears "there was a problem with this request" if I try to change anything.

I never had this with any earlier firmware and attempting to reinstall v1.1.8 doesn't change anything

Thanks, that rules out the most common causes, I recommend contacting support about this issue.
It may also be worth trying a different browser, I've checked using Firefox each time, maybe it behaves differently with different browsers?
Also because the new firmware added a new menu option, try clearing the browser cache for that AP's web interface (usually Ctrl+F5)

Thanks for the tip but it's not the browser - same on Firefox and Opera and I regularly flush cache anyway..

Whats the best route to contact support - I'd assumed they monitor this forum?

Thanks

The best way to contact support for this issue would be email support: http://www.draytek.co.uk/support/techquery