Finally managed to get the gearbox out of the car today. It's very grubby and seems quite oily around the front of it. I need to give it a good clean to start having a look over it, but I think it maybe a good idea to replace all the seals and gaskets whilst it's out.
Also, I wasn't expecting the clutch release bearing and pivot arm to drop off. Seems quite loose and wobbly so something else I'll replace whilst it's all off.