I don't know what other RSPCA branches are like. But years ago (1999) I was on placement at our local branch and a cat came in that they decided was semi feral. I was told I wasn't to go into the pen with him and if I did I had to wear gauntlets. So on my lunchbreaks I ate fast and then went into the pen. I wore the gauntlets while I was going in but as soon as I got in took them off.
I called this cat Louie. (Noone had name him.) When people entered the pen, Louie got nervous and sat in a corner; unfortunately it was the corner the door was close to so it backed him in, making him more nervous. I kept going in and after a week or so, he was calm and accepted fuss but grumbled sometimes. That's when I noticed the amount he was drinking so I mentioned it. Tests were done and it was shown Louie had diabetes.
After he was put on insulin his personality changed. But the poor lad was still only given a few weeks on the rehoming block before the branch decided noone would take him on.

The week after "the decision" had been made a really nice gay couple came in looking for a housecat with an illness that they could pamper - I nearly cried. Louies perfect home had appeared a week too late.
This example says it all about our local branch; they aren't prepared to put the time in with the animals that need it. Sad but true. Thankfully as far as I know not every branch is the same.