kitten crisis in east London!

My friend has had a cat give birth to four kittens in her shed. Her partner is allergic so she's been feeding them in the shed, where they have thrived. The only trouble is she can't get anyone to take them - 4 cat rescue places have said they're full. They obviously need to be spayed soon or the crisis will continue. She's trying friends now but does anyone know of any agencies around Canning Town who have any vacancies?
They're very sweet...

Thanks - I'll pass that on