Basically, long story short, I noticed lice, took both guineas to the vet, they confirmed it was lice and they needed invectimin treatment, they then went to quote the total cost and was looking at around £90 for their medication (for 3 doses over a course of 4 weeks for the two piggies), so they suggested to me to buy it from the shop, as long as it had invectimin in it. I have done this, treated them both with the first treatament two days ago. Today they were both taken to the vet again as Willow had a crusty nose and they just wanted to check honey was not affected by anything Willow may have. And obviously it was on their record about the lice, the vet then suggested to keep on top of the treatment with a shampoo, I didn't just want to buy any random shampoo and it not be worth it so wondered what others would recommend, and had seen a lot about the lice n easy one.