Well I have an update, and it's not good news as just got off the phone with the vets.
Apparently, as the cat had some nasty fractures it would have been a long road to recovery (and possible expensive one) so the owners decided to have him put down
I did question whether or not it was down a money thing, and didn't really get an answer, pushed again towards the long road to recovery and it was the owners decision.
So I dunno, maybe it's a good thing if the poor little guy was suffering, just glad I found him when I did and he didn't die dehydrating and suffering in a bush or long grass somewhere
Reading some of the replies below, it's good to know that he had lots of positive thoughts heading his way, and I do kind of agree with the fact that animals manage to cope rather well so should try to be saved where ever possible but I guess it has to be a personal decision at the end of the day, a bit like turning off life support.
But still a part of me thinks it may have come down to a money thing, but I didn't get the chance to express to the vets the intentions of possibly paying for the cat treatment ourselves (with possible help!) , owners decision at the end of the day, and considering I don't have any of the facts written down, I suppose I will never know the true reasons and the actual state he was in.
Would the outcome of been different if he wasn't micro chipped and had no owners, possibly, but again who knows!
On a slightly more negative note, I have just thought again that the owner never contacted me to so "hey, thanks for taking my cat to the vets, if it wasn't for you he wouldda... blah blah... "

Rest in peace CAT6