Ok so the update.
A lovely vet examined her very thoroughly. There was definitely crackling coming from her but not in her chest at all which indicated that something was in the nasal cavity and not her lungs. The vet felt the lump was too hard to be an abscess which I was wondering as my only other experience I don't remember it feeling like bone but it was a while back so who really knows.
The vet felt that the lump was much more likely to be cancerous and had spread into the nasal cavity. This would make sense with the weight loss but no loss of appetite. The vet was also able to check her teeth because she had no food in her mouth at all.
I was given the option of having x-rays for £150-250 today to find out or waiting for my usual vet and saving money. I was quite blunt with her which I think she was secretly grateful for as I'm sure it's a conversation no vet wants to have. I asked her about the outcomes, what if it was just an abscess, did she feel it was operable? She said no, if it was an abscess given her fraility and age and the proximity to the eye she would not feel confident in operating and Daisy surviving. So I asked her quite bluntly what the point in x-rays would be if the outcomes were the same and she was honest in saying that other than knowing what the problem was there wouldn't be any change so we decided it was kindest to stop her suffering there and not put her through anymore.
The vets were brilliant, they talked me through what they would do and offered to bring her out to the car for me to say goodbye. I declined that as I had already had a cuddle and said goodbye before they collected her from me.
It's an absolute shock still, she was our absolute favourite piggy. Such a fierce, strong personality but she was brave and loved keeping the humans in check as well. I've had several good cries already, I'm sure there will be more to come.