I do not own a Avenger bullpup, however I recently installed a Jake Bowman forward cocking kit on my Diana Skyhawk.
The results for me, a converted to lefty shooter was beyond expectations. As a result I feel the airgun world needs such products.
I just read an article about the AV kit and it appears to be a good option, if I owned the bullpup instead of the rifle I would buy one. When I bought the rifle it was because it is handier to shoot than the bullpup.
I also see the kits are sold out, which may mean something.
Good luck,
Roachcreek