forest is a bit wider than robert. here's an old pic i had on my phone:
the left is robert and the right is forest.
i prefer the robert last as it fits snug, but not tight. the forest (in the same size) feels looser even if i pull the places pretty tight. i might be able to go a half size down in the forest, but it would be harder to find since i wear UK7. i'll try to take a better comparison pic tomorrow morning.
here's another pic, but it's hard to tell that the forest fits wider from this view.