Great, the cooker end is a screwed connection, so no washer is right. Panic over.
I've only got access to the old one which is something like this:
http://www.screwfix.com/p/standard-ng-lpg-cooker-hose-4-1-2m/49514?cm_sp=Search-_-SearchRec-_-Area2&_requestid=1620956
Trust, but verify.