Just enter the Box 135 amount from one country. Then add a second T5013 and enter just the second Box 135 there.

Thanks - then do I add all the same information again on that one?

Also, now it's suggesting I can carry amounts over now if it applies for me; which when I hit the help button, I'm still not sure if I am eligible; do I just say yes since it seems to be discovering something it hadn't last time I did it?

On the second T5013, you only need to put in the Box 135 amount, the country and the fiscal period.

What is it telling you that you can carry forward?