His name's 'Rusty' apparently Tone. Comes up in a web search for: rusty trigger unit.
Back to the Mk4 FWB, I'd like to thank WD for offering me a go on the one he'd finessed. I honestly liked it.
Sure, it's not designed for the UK limit, but neither is the holy HW80. Or the Umarex Walther (branded) Century for that matter.
For the money, I'd rather have one FWB than two pot metal Umarexes...