This is my first post so please be gentle with me. I have just noticed the Zavvi online have the Wii Fit units at RRP available on their website. Delivery is free and dispatch is meant to be within 24 hours. They also say they're expecting units to arrive in their stores this Thursday (4th Sep).
Direct Link: http://www.zavvi.co.uk/games-wii-fit-page/i.jsf
I have just ordered mine and the order has gone through. Can't wat for it to arraive now!