English Art/Literary Poetry & Literature

She groped for an ornate speaking tube, but Moist took it gently from her hand, whistled expertly down it, lifted it to his ear and flashed her a smile.
[…]
A voice in his ear, faint as a spider trapped in a matchbox, said: ‘Scitich wabble nabnab?’
‘Hugo? ’ said Moist. ‘It’s good of you to make time for me. It’s Moist, Moist von Lipwig. Postmaster General.’ He glanced at the speaking tube. It disappeared into the ceiling. ‘So kind of you to assist us, Hugo. It’s these missing letters. Five missing letters, to be exact.’
‘Scrik? Shabadatwik? *Scritch vit bottofix*!’
‘Don’t really carry that kind of thing, Hugo, but if you’d care to look out of your window you’ll see my personal assistant, Mr Pump. He’s standing on the other side of the street.’
And he’s eight feet tall and carrying a huge crowbar, Moist added mentally. He winked at the lady
sitting at the desk, who was watching him in a kind of awe. You had to keep people skills polished at all times.
He heard the muffled expletive through the floor. Via the speaking tube it became ‘Vugrs nickbibble!’
--quoted from Going Postal (2004, fantasy fiction) by Terry Pratchett (link: http://www.8novelsread.com/read/going-postal/334910)

Sorry for the length, but I have to. The context is that: Hugo, who said the weird words, had stolen some metal letters of a slogan sign from the post office to make his own sign, and Moist, Postmaster General, asked Hugo to return the letters with threat and succeeded, despite his reluctance.
The three lines said by Hugo were distorted by a speaking tube and became a voice "as a spider trapped in a matchbox", so left me three riddles to be cracked.
Now, the first line "Scitich wabble nabnab" may be "Is it corporal Nobby Nobbs". Here is my question about it: https://chi.proz.com/kudoz/english/poetry-literature/6586483...
The third line "Vugrs nickbibble!" may be "buggers nickable". Here is my question about it: https://chi.proz.com/kudoz/english/poetry-literature/6586031...

"Scritch vit bottofix" is the third part of the second line to be cracked.
Thank you very much for your participation!