Yes that was me, I work just next door to them.  Was slow to notice your wave as you went past but i did try to wave back   
  
I was thinking the same thing about yours when I caught up and you let me pass, looked stunning.  Got me thinking about some new wheels now. 
  
Yours is the 2nd black Z that I spotted today, the other was northbound on the A34 then turned off onto the M40 around 8:40 this morning.