[Carshay]

Poor Lilian has been looking a bit puffed up for a couple of days and now has some bleeding from her vent. She's been eating and drinking quite normally but I have separated her from the others. She's a three year old hybrid (goldline) if that means anything but I'm not sure if she is still laying or not as I have 13 chicks and 6 of them lay the same colour eggs! Her vent looks ok although it may be protruding a little - certainly not prolapsed. I don't want to lose her as she's nice and friendly so any advice would be gratefully received!

[joyfull]

it sounds like an egg has broken inside her and the others have been trying to eat it. You did right to separate her at least until the bleeding stops. To stop it you need wound powder (in an emergency cornflour will do) and then use purple spray to disguise any redness.
You now need to see if there is any egg left inside her - you could try sitting her in a sink filled with warm water for 30 minutes to see if she passes any more or lube up your finger and feel.