We setup a new 2830n here and shipped to the client. When accessing it now, the wireless network option has completely disappeared from the menu on the left.

To eliminate browser issues we have logged in remotely and from a PC within their network with different browsers.

All other router settings are as we set them. We have also upgraded the firmware to no avail.

The issue is that we can't reset this router without someone on site as the user won't be able to input any settings themselves.

Is this common and any ideas how to fix without a replace/RST? Is there a command I can use with telnet to enable menu options?

thanks

There are 2 models of 2830 ... the sb (single band) & db (dual band)
To find out which one is ... check this guide
http://www.draytek.co.uk/support/kb/kb_vigor_2830_dual_band.html

Sometimes (mainly the client) loading by mistake wrong firmware ... so if the model is sb & load db firmware the wifi may not arrear or rice versa
Check the model from the guide and what currently firmware is

Replace/reload the correct firmware for the right model ... but should use the *rst* file only in cases like these ...

If you trying remotely may not be good idea because you will need someone at the other end for the settings because the *rst* file will delete all settings
If you try via the WUI is ok ... but personal i will say the best way is via firmware utility tool

Get the Firmware Upgrade V.3.6.5 (Windows) tool from UK support (down of their page, guessing you have windows) ... unzip it

Latest firmware is 3.6.4.1 for the sb model
ftp://ftp.draytek.com/Vigor2830/Firmware/v3.6.4.1%20single%20band/annexA/
& 3.6.4 for the db model
ftp://ftp.draytek.com/Vigor2830/Firmware/v3.6.4%20Dual%20band/AnnexA/

follow this order to avoid time outs (have the upgrade tool ready and stand by first)

-Disable temporary firewall at pc
-use ethernet cable & not via wifi

-open the utility upgrade tool 3.6.5
-Check the ip with use the search/browse button right of the box where typing the IP address ...if not appears the IP after the search try & type 192.168.1.1
-load the rst file(should delete all settings from mismatching the wifi issue)
-password leave it blank or try admin
- leave the upgrade tool open & stand by ...

While the 2830 is off ... press and hold gently the small reset hall button ... turn on the modem while the reset button is still under gently press ... and while the leds flashing ... let go the small reset button ... and press the send button at the upgrade tool before the leds at modem stops flashing fast

sorry did not release you was trying remotely ... someone must be to the other end with little basic knowledge to enable at least management with telnet etc and give you the external ip address ...

my thinking is

use the rts file to clean up everything and instruct the client how to log in & to use the quick start wizard only for the adsl part just to connect & give you the external ip and also him to log in & enable management (telnet, http, etc) ... after is easy to set it remotely
or
from your end to enable everything at remote management (telnet, http,ftp etc ) & just try the *all* file .. it should still work to bring back the wifi ... but is recommended the *rst* for broken firmwares if this is the case
http://www.draytek.com/index.php?option=com_k2&view=item&id=1214:faq-article-1214&Itemid=293&lang=en

If is not mismatching firmware issue then is fine just to upgrade remotely with the *all* file ... no worries