In the 70s my jazz trio played a gig in a park in Chiswick or Hammersmith, and Carter's Steam Fair was also there, and plenty of time for me to have a good looksee. I did not know anything about J40s then, but was mightily impressed that the cars were so much more realistic than usual ones. I don't think they were painted like that though, rather more down to earth. Those do look a bit garish to me, but great for kiddies.