Unable to connect to wifi networks

After upgrading iPhone 5 from iOS 6.1.1 to 6.1.2 I am no longer able to connect to some wifi networks. My home network via an AirPort Extreme is fine which is where I upgraded to iOS 6.1.2. But I can no longer connect to my work office wifi and tech support are stumped as I used to connect using iOS 6.1.1. The network is password secured and I am expecting to be prompted to accept a certificate but am not. There are no active Profiles on the phone. My iPad (iOS 5) connects  fine to the same network using the same password.

In addition I cannot connect to a hotel network which prompts with a login page on my iPad (iOS 5) but I get no such login page with my phone, it just fails. All attempts show message unable to connect.

I have tried various fixes including Reset network settings, Reset all settings, disabled cellular data, a hard restart, flicking airplane mode on/off. I am trying to avoid a factory restore.

Thanks