Thank you for helping this stray cat.
My name is Rebecca. I am a veterinarian, and will do my best to help.
What you describe is not unusual in long haired cats. If they get matted down to the skin, the mats eventually peel off like you are seeing.
The only way to prevent it would be regular grooming, and if he won't trust you yet, you can't do that.
Some owners of long haired cats will have them in every spring to be shaved down.
I am not seeing responses from you. I hope you see what I am writing!
These long haired cat will form these clumps when the fine undercoat sheds and gets tangled in the longer outer "guard hairs".
I will try another way to connect with you if I do not hear from you soon.
Hiya thankyou for your advice, sorry for the late reply, had to nip out. But this helps as it was quite alarming to see such large chunks of fur coming off, and we hadn't seen this happen to him before and didn't know if we needed to take him to a vet, which would have been quite difficult. So we will just keep an eye on it for now
Thankyou for your help.