The SPFL have claimed Rangers chairman Douglas Park made a "threat" to league chief-executive Neil Doncaster.The league body have written a letter to Scotland's 42 clubs in which eight out of nine board members have now opposed the Ibrox side's EGM resolution.The letter also alludes to "gross breaches in confidentiality" relating to the widespread circulation of Rangers' document on Thursday, insisting it contained private information.All 42 senior sides will head for the ballot box on Tuesday to deliver a verdict on whether the league's governing body must face an independent investigation into the handling of the season-ending vote.But in a series of detailed responses to Rangers' dossier, the SPFL have made an allegation against Ibrox