Have you tried looking on the easyJet Staff Travel Website?
It says on there in the automatically scrolling text:
JUMPSEAT TRIAL CONTINUES
A trial for some easyJet staff to be able to use the Flight Deck jumpseat for staff travel on fully booked flights is now underway and will continue for the next few months. All other staff who are eligible to use this facility have been asked to register their interest in the facility by email to ????????@easyJet.com
If you meet the criteria below, please register your interest:
*You are based away from your country or city of birth and could fly home using easyJet staff travel
*You have a full crew airside pass (yellow stripes)
If you have any questions or comments about this facility, please email ????????@easyJet.com
(I have removed the email address so that only easyJet employees can gain access).
Also, if you read the Interactive Questions and Answers (again on the staff travel web site) it explains exactly where the jumpseat travel policy is at.