The gun was supplied and sold to me by Woodfield. I remember Will saying he had degreased the internals and lubed everything himself prior to sale.
He is an authorised dealer and infact has the title 'Walther' on his banner advet on this site.
The dieseling was not bad and lasted a short time.
I'm no expert and really all I can do is state facts.
The fact that Will had the rifle back, stripped it down, replaced the parts he thought might be the problem but still failed to get the gun shooting above 10ftlb indicates to me that there was some sort of engineering type/manufacture type issue with it.
The service from Will was excellent,, great guy, I've had several guns from him in the past. Umarex have responded to the issue via Will rapidly and reasonably.
The point I want to share is tha I bought a new Walther LGU that suffered from low power output and it could not be repaired by an authorised Walther dealer.