Worth a shot I guess, but I don’t understand why? It's only the 1 add, I'm trying to edit it, not make a duplicate

 Nope, didn't work

 delete the ad and start again?

 Seems like the only option I guess, ah well, hadn't written much anyway!

 So you see the message is telling you: You already have an ad with that TITLE or DESCRIPTION. Since the description you have there is "Description and pictures coming soon", your other ad probably has the same description. Also in the error message the part "an ad with that title or description" is a link that would take you to the ad with the similar info.

 Ah ok, apologies then, looks like it was a mistake on my behalf, thanks for explaining Radek