Chief Guinea Pig
Senior Guinea Pig
Agree with Helen and @My3cuteBoysYou would need to keep them away from the children for at least 6 weeks and that should include being in a separate air space (so a different room that they don't go in). You would most likely need to start treatment from scratch as Pets at Home vets will not have treated it systemically and most likely only used a cream. This means it will return if not treated properly. They would need Itrafungol from the vets who would charge about £70 a bottle (though it can be found cheaper online with a prescription). The full course would take 6 weeks (on a week on week off basis - it carries on working in the week off) if you were to follow the advice of my vet and the company who make it. Though other vets suggest a shorter duration. The fungal baths and Imaverol dips would need to be done weekly with topical application of Imaverol daily. You would need to wear a change of clothes for handling and clean the cage every day with F10 and change and wash any bedding too at the highest temperature possible.
If you don't take these pigs in they will likely stay in quarantine for a few weeks and will then be placed in the adoption centre with the other affected pigs with a sign saying "I was poorly when I arrived here" or something along those lines.
You do not want to catch ringworm yourself, and the care and precautions are something you do not want to have to do when you get your new piggies. It will be a lot of hassle for you, and most likely will regret your decision if you take them on and you find it too much to cope with.