Help Sapphire see a Heart Specialist

Hi, I am Sapphires owner, as a student at University Sapphire used to visit our student house, while at first she was very skittish she came to be a permanent part of the house, coming whenever she heard us in the garden. She seemed well kept, however one day I had a very bad feeling when it had been raining, she was soaking wet and breathing hard. After this she seemed to be okay, however it was always in the back of my mind. When it came to moving out of the house I didn't want to risk leaving her there if she didn't have anyone else, so I scanned her and found her 'owners', which turns out had not seen her for 3 years. The most loving cat, had been alone for over 3 years and the owners could not take her back due to their cat not being friendly.

I was more than happy to take Sapphire, but with over a year left of university she went to live with my parents and their cat, which she loved and was very comfortable (once she was re-domesticated), although I had to call my mother every day to see her and often travelled home purely to see her because I missed her so much.

Once finishing University I found a house especially for Sapphire, where pets were allowed and she would have plenty of space, however 2 months in she was not eating, breathing heavily and not really moving.

Me and my partner rushed her to the vets where she was deteriorating quickly, at first they thought she was just constipated and sent her home with some pain medication - which didn't really make sense. A couple of days later she was even worse and so we went back. This time she was taken for scans as they could barely hear her heart beat.

(Photo above is Sapphire after one of her drains)
Once the scans were done it was found that she had pleural effusion as well as pericardial effusion, which was drained however the vet could not find the cause, listing many things it could be and recommended waiting to see how things went.

Sapphire was back to her old self, demanding, scoffing her food and ensuring she was laying with me at night to set my allergies off, all worth it for the cuddles.

2 months later the signs were coming back, no where near as bad but we drained the lungs and heart again, still no closer to a diagnosis (heart disease, tumours, idiopathic or fip) I was told at this point it would only get worse and I would be back in a month and so I needed to say goodbye.

Sapphire then went for 4 months with no signs of stopping, but then showed signs again, leading to February 3rd this year. This led the vets to saying it couldn't be FIP due to her still being alive, however they still could not tell me what was wrong with her and said she would need to go to a specialist.

Unfortunately the 3 drains so far have already cost near £1,500 and it is impossible for me to pay out the required amount to get her to the specialist for the help she needs. This will require travel, multiple scans and possible surgery but I cannot give up on her because apart from this condition, the vet has said she is completely healthy. If this is something I can save her from I will, she has only just turned 7 and will have great chances of living a life if she can get the help she needs however after covid and finishing University I'm not in a position that allows me to find this money as quickly as I need to.

I can't say goodbye to Sapphy, she is a fighter and she will get through this, she will live a fantastic life not being a stray, the most loving cat will not be beaten by this, anyone who knows me knows how obsessed I am with this cat, and any help will always be appreciated.