I posted something on your other thread about an exotic vet in Suffolk - they specialise in all exotics including rodents - in Suffolk
Suffolk Exotic Vet
I would be very careful buying any mite treatment. I am not sure the stuff sold in the shops is the same as the Invermectin the vets prescribe. And sometimes a vet can give an injection rather than topical treatment. Is it "spot on" you bought.
See how she goes over the next week, as she's had the stress of a vet visit and a cage clean, and then maybe think about taking her for another opinion to the exotic vet. It might be something else and/or they may prescribe the correct topical treatment or give an injection.