Maybe Sherl had other things to do this weekend (like sort out the aftermath of the Charity Golf Day) rather than update a rivals message board on news of the takeover?
They also filmed some bits at Canary Wharf back in April. I would guess from the location and cars that it was some kind of "Cars for Credit crunched Bankers"
http://www.flickr.com/search/?q=canary%20wharf%20top%20gear&w=all