Well... I'm sticking with 50m, cause I really want to have a go at the round under competition conditions, and from the phrasing of the email (I'm assuming it's the Surreys??) the official compound round will be the 50m, with the compounds simply being allowed to shoot 70m if they wish (in the way gents can shoot lady rounds and visa versa)
So we have the first example of a comp with a Double 50m round now offering (but not replacing with, to their credit) a Double 70m round to Compounders as well. Be interesting to see how many non-squad 50m shooters there will be...