Thanks all for your advice and good luck wishes. I really want to help these cats and I have to say it's all because of the people on this forum that have inspired me to do it. I never would've thought to do or would've been too anxious about it before.
But reading so many stories about people on here has been so uplifting and inspiring, seeing others helping ferals and rescue cats that I want to do something myself to make a difference to these cats.
I did wonder about them getting wise to the traps so i will discuss this with Fran who traps them. I'm quite excited about helping the cats as I do like them even though I can't touch them and interact as such.