[Hammy992]

Thanks Cypher and Hamsterhugger x
That was the impression I got from what the vet said; that although the cysts themselves aren't painful they can end up causing secondary pain through increasing compression of their organs, which is why having surgery is so vital for their comfort. His swollen belly has definitely slowed him down but he still tries so hard to potter around his cage. He is sleeping more; it must be uncomfortable carrying that extra weight around.
I did have to laugh a bit at one of the xrays she took with just half his body in it as he kept moving around in the box; only a piece of sweetcorn got him to sit still.
I have gone ahead and booked him in for the day the vet gets back in 2 weeks time, just to ensure he can be seen to if I do decide to take him in for the surgery. Hopefully this diuretic will be able to provide him some relief and get him through this.