Course and slope rating - anybody know the easier and harder courses in the UK?

Ok I'm with you up to here. Using the Southerness example above and compare to my course Silloth on Solway.

If we use Silloth blue tees and Southerness white tees since the yardages are with 50 yards and the course rating is identical at 72.6.

Silloth slope is 136 and Southerness slope is 131. I would be playing off 6 at Silloth and 9 at Southerness