Okay, so after a stressful trip to the vets (but much needed trip) he DOES have an RI, but the vet was very good with him. She gave him two injections and we're giving him oral antibiotics for the next two weeks. Hopefully it won't stress him out too much...

I feel SO bad. He was so well behaved, he took it like a trooper. She was pulling him around and me being me I'm not used to seeing him handled as forcefully as that (I'm just good for a climbing frame for him lol) and when she gave him the injections he tensed like mad and wriggled and I had to hold him still... When she was holding him he kept trying to get away and headed straight for me every time.

He is currently curled up in his viv, looking like he may feel very sorry for himself. They said we caught it really soon, I was imagining the discolouration in his mouth and that his lungs seemed a bit raspy but other than that he is a perfectly healthy snake and we're doing everything just right.

Phew. Fingers crossed these antibiotics work then! Thanks for the messages guys