What I don't figure is why anyone would want to pay an MP a bung of £100k a year unless they expected them to have a word in someone's shell like to drum up some business.

I mean you're not paying £100k just to have the geezer's name on your company letterhead. An MP's name isn't worth diddly squat and as for a Lord, I'd expect them to pay me to have their name on my letterhead.