I more or less agree with everything that Tom Bliss and Will Fly have said !!
   I usually manage OK in most types of session,once I have overcome any initial hostility (if there is any) on entering the room with a cased or bagged guitar ; " I see you've brought your golf-bag with you !" is a typical comment that I have received ! One just needs to be a bit thick skinned about it,and generally I find that,once other players become aware that one is ,if not brilliant,then at least fairly competent (my own self-assessment !),then things soon become more convivial,especially if one actually "leads off" a tune ; "Seven Stars",in an "English" session,usually does it for me.
            Irish sessions can be tricky,yes,although I was lucky,when first attending the noted Irish session in The Herschel Arms,in Slough, to have "resident" guitarist Frank Docherty as a mentor,and was able to watch,listen,and learn from him !
       I still think I'll continue to give The Radway a miss,though------- too much hostility there !!! Up 'em !