My brother did Knockhill on a works event. Absolutely loved it. Said it is one that could catch you out very easy first time out. He drove with an instructor as a passenger who talked him through it in a Seat Leon. It might be the corner my bro was telling me about, where you start to turn right before you even clear the crest of a steep section. I may be wrong. He would love to go back. It's a good drive from Northampton though.