Gowers, himself an Englishman, said that  in Scotland, its land of origin, the pronunciation is skawn , and English people who know this so pronounce it. 
( Gowers ( , ( ( himself ( an Englishman ) ) ( , ( ( said ( ( ( ( ( ( ( that ( in Scotland ) ) , ) ( ( its land ) ( of origin ) ) ) ( , ( ( the pronunciation ) ( is skawn ) ) ) ) , ) and ) ( ( English people ) ( who ( know ( this ( so ( pronounce it ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (NP (NNS Gowers)) (, ,) (S (NP (PRP himself)) (NP (DT an) (NNP Englishman))) (, ,) (VP (VBD said) (NP (NP (NP (DT that)) (PP (IN in) (NP (NNP Scotland)))) (, ,) (NP (NP (PRP$ its) (NN land)) (PP (IN of) (NP (NN origin)))) (PRN (, ,) (S (NP (DT the) (NN pronunciation)) (VP (VBZ is) (ADJP (JJ skawn))))) (, ,) (CC and) (NP (NP (JJ English) (NNS people)) (SBAR (WHNP (WP who)) (S (VP (VBP know) (S (NP (DT this)) (RB so) (VP (VB pronounce) (NP (PRP it)))))))))) (. .)))
Gowers is a Frenchman so he doesn't know how English people say it.
( Gowers ( ( ( is ( a Frenchman ) ) ( so ( he ( ( does n't ) ( know ( how ( ( English people ) ( say it ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Gowers)) (VP (VBZ is) (NP (DT a) (NNP Frenchman)) (SBAR (IN so) (S (NP (PRP he)) (VP (VBZ does) (RB n't) (VP (VB know) (SBAR (WHADVP (WRB how)) (S (NP (JJ English) (NNS people)) (VP (VBP say) (NP (PRP it)))))))))) (. .)))