I'm having the same problem with my three, they are nine months old now and since the weather has been warmer and they are going out more I've got huge problems. I've sprayed the house and treated them again.

On advice from others on here, I'm going to take mine to the vets to get the Frontline Combo, its a prescription flea treatment, I know its more expensive from the vets but apparently the vet can issue a prescription that can be used to purchase online for the next six months or so. I'm also going to get a house spray from the vets to treat again.

Its such a horrid problem though and I hope we are both successful in getting rid!

Louise x