when it comes to babies the truth is that an expensive rug is not the wisest investment...my advice, if you have your heart set on something gorgeous and pricey wait until you pass the sicky and potty training stages (not very glamorous but oh so true). in the mean time, cheap and cheerful will do the trick (and these ones are cotton too, so nice and natural)...
  vertbaudet target circular cotton rug nursery kids room pink green brown purple babystylefile baby style file 

round rug, £29, vertbaudet