Do a search on airgun forum, a guy's posted a few comments about his on there.
From what I can gather the suppressor does work but as with with all springers you'd be better reducing mechanical noise from the gun itself (twang, boing!)
The trigger is a bit of a pig on these also.
Luckily Woodfields offer upgrades to sort both
http://www.woodfield-gcp.co.uk/index.html