Thanks to both of you for your input.
Apologies - yes you are correct about it not being a STD patch - don't know where I pulled that one from!
Thanks for the tip Gil - here's a photo with a small but powerful 3 x LED bulb torch behind the patch. I have positioned one of the bulbs behind the white chute canopy, as it appears to be the original cloth patch material and not to have been printed, and the other 2 bubs at the 10/11o'clock position behind the red print beside the canopy to give a comparison of how much light is coming through between printed and unprinted ar