Feral (I think) cat/kitten problem

Around 3 weeks ago dd1 spotted a cat and 3 kittens around 6 weeks old under the fence in a corner of her garden which abuts her neighbour. They subsequently disappeared. but on Friday last week dgd saw one of the kittens under the garden shed. She fed it and it shot back under the shed again-no sign of the rest of the family. Dd1 was leaving for holidays on Friday evening so asked me to keep an eye out, maybe put food down and she would sort it out when she got back. Problem is that dd lives about 10 miles away and I can't guarantee getting across there every day. I thought about getting Cats Protection involved to try and trap the kitten, but not sure if dd would welcome strangers around the property when she's not there. I've text her to ask the question but no answer in 24 hours!! DH and I took cat carrier over yesterday to try and trap it but no sign. Hate to think of it being cold and hungry at around 8 weeks old