OTA updates can vary, and in my experience be a little unpredictable. However, since you have a Polish ROM, your geographical region is irrelevant to the Samsung firmware and you will receive an update notification. As per your comment, since you are all stock then you can download and install the update.
If you want your official UK firmware there are 2 options really:
- Wait until the UK gets an update, download it from SamMobile and flash it via Odin. As per your current setup if the UK ROM gets an update you can install it as normal.
- Revert back to your most up to date stock ROM, and download the UK OTA when it is available. You will receive a notification as usual.
If you have a custom recovery you will need to revert to stock. It is the same as the second bullet point above: download the stock firmware and flash via Odin (PC) or Heimdall (Mac / *NIX).