Anyone who has had a life will have done something at sometime that they are ashamed of. The three charges aimed at Boris were;
Made something up as a journalist - so what, don't they all.
Lied to Howard about affair - Boris denies this but if true so what - none of Howard's business
Agreed to supply address of journalist to Darius Guppy so said journalist could be beaten up - agreed but didn't supply address so no harm was done.
These three things are hardly a big scandal and none of them are against the law. IMO this does not make him a 'nasty piece of work'. If this is the extent of the skeletons in Boris's closet then I would say he has nothing to worry about.
Having watched the recent documentary about him I think he is very cunning - cultivating the image of a buffoon whilst at the same time being very driven.