Sensor clean - Copper hill questions

Hi Folks,

Despite owning my D700 for a number of years now I have never cleaned the sensor!  Well I am guessing it's about time as there are a few (several) spots noticed when looking at a white wall pic at f14 (not in pics at normal f numbers though).

I am looking at copper hill and see they send the kit International but wondered if this is available in UK?  Also they say the spatula size for first timers is 18mm, but experienced cleaners can use 24mm.  Should I just get the 24mm size?  The 18mm is not going to cover the sensor?

Kit will be used to clean D700 and D800.

Sorry for the basic questions but I am a first timer when it comes to cleaning sensors!

Thanks for your help.

Cheers, Mark (winter1)