"Ring Up the Curtain, Being a Pageant of English Entertainment Covering Half a Century" by Ernest Henry Short and Arthur Compton-Rickett, 1938, says:

"Bill Sloggins," better known as "He's all right when you know him," was another Coborn "hit." The chorus was introduced by a snatch of East End dialogue:

"Say, Jack. 'Ave you 'eard the noos? Bill's cut 'is wife's froat."
"No! 'Ave 'ee?"
"Yas!"
"Well, 'e warn't a bad sort, arter all, warn't Bill, when you knew 'im."

CHORUS: "'E's all right when you know 'im, but 'e's angry when 'e's vexed.
'E'll black your eye one minute, but 'e'll stand a pint the next.
'E wouldn't 'urt a baiby. 'E's a pal as you can trust.
'E's all right when you know 'im, but you've got to know 'im fust."

--From Google Book Search.