How about this as an idea...
You order a new machine or the core components from OCUK
and then you arrange to collect from the store on a day when an overclocking course is arranged i.e. when say 10-20 other people are also collecting and attending the course.
Then staff at OCUK help you assemble and overclock your new kit.
You leave the store with your new machine build and overclocked and with some knowledge and fun along the way.
Would that not be a great day out?
I can see this working for both overclocking and watercooling. I recall how scary doing my first water loop was and think I would have been much happier had someone been there to ask and check things over.