I've raised £1000 to diagnose our two young cats with an unknown condition that has caused hind limb paralysis in one and is now affecting the other.

Lexa and Luna's Story - please click here to see the video footage of their story.
Further footage of Luna attending hydrotherapy - please click here to view Luna braving the water.
In October, we adopted two kittens from Cats Protection Gildersome - 'Lexa' and 'Luna'. Lexa had a slight head tremor from birth but Luna was healthy. On 8/11/16, we noticed Luna was walking as if injured. Over the next few days she began to walk on the tops of her paws as opposed to the pads and it rapidly went from just the right hind paw occasionally, to both paws, every step.
We tried broad spectrum antibiotics to reverse whatever was causing this but nothing worked and Luna's condition deteriorated to the point where she now 'walks' the way a baby crawls.
In December, we took Luna to our vets who had no more ideas as to what it could be. Instead, they said the only way to know would be through an autopsy which was possibly the worst thing to hear at that time and was incredibly upsetting.
After asking if there was any other option, we were referred to a specialist. He was completely baffled too and wanted to film Luna for his veterinary students as her presentation was so rare! He gave us a quote for a series of tests - over £2000. Luna is insured but her condition had begun within a time-frame that our insurance company refuses to cover. It was awful, to say the least. We had her fully covered thinking at worst she'd get some arthritis at 12 years old but now we didn't know if she'd even reach her first birthday. We were now facing a serious neurological deficit that was taking her mobility away from her and were unable to afford to diagnose it.
Now her front limbs are weakening so she has splints for them and we take her every few weeks to hydrotherapy and physiotherapy to try and keep her muscles from wasting due to immobility.
We need your help to save her. The vets don't know what's going on without these tests and we just can't afford it.
Lexa is now starting to walk this way too. It seems that Luna has possibly passed it to Lexa and we could end up losing both to this awful condition. We therefore are very much hoping/praying that some kind people can help our young cats to get the quality and length of life that they deserve. Thank you in advance for anything you can give.