Gavin your EV2 will be PCP if you want to shoot in a graded class (Doing the Standers and Kneelers as per BFTA rules).
The OPEN class is if you cannot (or don't wish to) do the Standers/Kneelers in their approved position. Instead you can do the entire course in any of the approved positions, what ever you wish but most do them all sitting!
Hope this helps!
AA Field Target Team 2007~2011
East Devon FTC - SWEFTA Club Champions 2006/2007/2008/2009/2010 & 2013/2014/2015