My Wally had pneumonia. My vets contacted various specialists, including Molly Varga and Simon Maddock.
I don't know whether it can be of any help, but this is my experience with Wally....
Wally was on Marbocyl (recommended by Simon) and duphapen daily. He was also on Corvental twice daily (recommended by Molly Varga) to open up his airways.
At his worst we had to nebulise 3-4 times a day with F10 in saline. We used a carrier as a nebulising chamber as the mask was too stressful for him. Any stress would trigger mouth breathing episodes. I bought a nebuliser from Maplins, it was around £50.
He was also on 0.9ml metacam twice daily (he was 2.4kg)
Wally was diagnosed last November and he lost his fight last week.
He was a very poorly rabbit when the problem first came to light. With Wally the problem was chronic and the bacteria had been wreaking havoc in his lungs with no visible external signs, he coped with it in the early stages and hid it well. It was only when his lungs were so damaged that we started to see external signs, such as mouth breathing, reluctance to move, etc. The bacteria leaves damage that does not heal. From the reading I have done, sadly this is common with bacterial lung infections, by the time you can visibly see there is a problem, the damage is already done and is irreversible.
Wally was initially hospitalised for two weeks, he had oxygen therapy frequently to help with his breathing. His prognosis was extremely poor, but my vets managed to stabilise him with aggressive antibiotic therapy. When he was allowed home, we continued his medication and nebulising. He was happy and comfortable, but didn't have the lung capacity to run, jump etc.
Since November he has had two relapses. He came through the first one with another month long course of antibiotics. He relapsed again two weeks ago and although he initially seemed to be responding the the antibiotics, he then began to deteriorate and we had to make the decision to let him go. After he had relapsed a second time, the damage in his lungs was just too much.
It is good that P@H are paying for treatment. Wally's bill was £1200.
It is a horrible illness. I really do feel for you.
These upper and lower respiratory infections seem to be absolutely rife at the moment. It's a very frightening situation
Sending lots and lots of vibes and good wishes to your little girl xx