Upgrading to Lollipop on sgh-1337 (Samsung S4)

I want upgrade my mobile to Lollipop, currently 4.2.2. It is an import AT&T phone (sgh-1337 ) unlocked and am in the UK.

I can't use the upgrade procedure presumably because of being in the wrong country. There are upgrades available for AT&T but I am assuming that will take me back to the AT&T settings. So maybe I should look at a Custom ROM for the model but am not sure about the practicality of that.

Any thoughts welcome

 

There are various ROMs for download here.

 

Thanks Roger - hadn't come across that one. Will see if I can get my befuddled brain around it