Managed roaming - caused by flashing rom?

[neill_bowler]

Hi,

I recently downgraded the OS on my Xperia M2 to Jelly Bean. That is something like this :
Device Name : Sony Xperia M2 D2303
Date Update : 2014-05-28
Region Code : CE
Region Country : Central Euro
Firmware Version : 18.0.C.1.13
OS Name : Jelly Bean
OS Version : 4.3

Now on many a level this has worked fine. I have much more internal storage available, and there's not a lot of difference between Jelly Bean and KitKat.

However, ever since doing this I get the following popup every time my phone loses signal.
Managed Roaming
Network with Limited Service found. Do you want to initiate a Network Search?

Does anyone know what's causing this and how to stop it? Since I live in the UK I am wondering whether it's because I installed a central Europe ROM?

Thanks for your help,

Neill