Just for a bit of fun, here is a proposed equality, that sedburgh time in reasonable conditions is similar to marathon time.
I’ll enter the running by saying In a year I did mid 2.50 on marathon, I just beat 2.50 on sedburgh. I forget the exact times.
Many years later I plodded a marathon in around 3.30 I recollect just beating 3.30 at sedbergh
Who else has comparison times?