Kellogg's and copyright

Okay. Five years ago, I did a big piece of artwork. It was a self promotional piece printed in Contact. (Contact is a kind of directory for art buyers).  I subsequently received a lot of artwork commissions resulting from this ad. End of story. All tickety boo...  or so I thought.
Last year sometime, I was doing the weekly shop in Waitrose, bought some cereal and was shocked to see this artwork on the back of my packet of cornflakes.  Okay, it's not my artwork, but the similarities are plainly there for all to see. The elements are all there. Was this copying? Was this infringement? Plagiarism?
I still feel cross about it.
Try and spot the similarities. There are many. From veluxes to dogs, to skips, to men working in a hole to names on buildings. I'm still wondering whether I could have taken this further! Why couldn't Kelloggs have simply asked me to do it?! Or at least asked my permission beforehand, and sent me some Golden nugget vouchers or similar.
Ti's a cruel world.
Check it out, as they say... spot the similarities.

Click here to see the pictures side by side.

Phill's promo piece
Cereal piece