Are there any fundamental differences between the configs applied to the SRP521 & 527?
The reason I ask is that there seems to be more options disabled from the "cisco" user (once the Xnet config is loaded) on the 521 than the 527.
On the 527 there was a Web Access Managment section in the Admistration settings where http/https access, as well as disabling WiFi admin access could be configured. This doesn't seem to be accessible on a 521.
Judging from your comment about the 521 having wireless disabled you are either in a fibre subdivision or you have been setup as a fibre 521 instead of a general use one.
For fibre wireless is disabled by default as the the box sits inside a metal cabinet and acts a a gateway not a wireless device. Having said that you can ring the helpdesk and request they activate the wireless for you if so desired.
Network Support WorldxChange Communications www.xnet.co.nz
It is the Web Access Management settings that are not accessible. One of the settings (as an example) in this section is the ability to restrict admin access to the router from a WiFi client (must be on the physical LAN). Another can restrict to https access only for admin.
Logging in using the admin user, these settings are accessible, but once provisioned (leaving only the cisco user accessible), you don't get access on a 521, but did on a 527.