Green’s Dictionary of Slang

(UK Und.) the robbery of shop tills.

1868		‘Six Years in the Prisons of England’ in Temple Bar Mag. Nov. 537: Why, ‘lob’ means a till, and ‘Peter’ means a safe. Stealing the till and opening the safe is what we call ‘lob-sneaking’ and ‘Peter-screwing’.
1873		Sl. Dict. 217: Lob-sneaking stealing money from tills; occasionally stealing tills and all.
1896		A. Morrison Child of the Jago (1982) 195: It was outside there that Ginger Stagg was pinched for lob-crawling.