I have this same issue. I am using an HTC One(M8)(Windows Phone version) using the default browser, IE. The default user agent is
Mozilla/5.0 (Mobile; Windows Phone 8.1; Android 4.0; ARM; Trident/7.0; Touch; rv:11.0; IEMobile/11.0; HTC; HTC6995LVW) like iPhone OS 7_0_3 Mac OS X AppleWebKit/537 (KHTML, like Gecko) Mobile Safari/537
Unsurprisingly, I can recreate this using Firefox on my desktop using this user agent. If I use the following user agent, the site is displayed as mobile, without the banner:
Mozilla/5.0 (Mobile; Windows Phone 8.1; ARM; Trident/7.0; Touch; rv:11.0; IEMobile/11.0; HTC; HTC6995LVW)
Note I removed the
Android 4.0 and the
like iPhone... sections. It appears that removing either is insufficient, but removing both removes the banner.
However, changing the user agent on my phone is either difficult or impossible, so if this could still be looked into, that would be great!