I found a bit of reading on google about that circuit and they also said it doesn't look "the best" and would be prone to not working correctly.
MY change would be - using the original circuit - to put the LOAD between the annode of the SCR and the collector of Q1.
Though also not 1oo% guaranteed, I think it would be better in some ways.
But what you really need is something to turn off the power if there is a short.
My modification would stop the power if there was a quick short, rather than a full on continuous short.
Ok, I shall stop talking now.