Oh wow, this is wonderful thank you! It installed fine in my Manjaro Stable Lappy & my Arch Tower. A minor quirk, which i guess probably comes from this not being a native Plasma app, but LXQt instead, was that it did not add a menu item. That of course was easily fixed by the usual simple expedient of creating a new app item therein, with its command being
/usr/bin/lxqt-admin-user. It works a treat!
I've now re-removed that naughty gnomie thaing.
Oh, ha, i see that the launcher quirk was already mentioned.