class 2
(d) Inflammatory bowel disease
Applicants with an established diagnosis or history of chronic inflammatory bowel disease may be assessed as fit provided that the disease is stable and not likely to interfere with the safe exercise of the privileges of the applicable licence(s).
from here
Digestive Guidance Material | Medical | Personal Licences and Training
see also
http://www.caa.co.uk/default.aspx?ca...0&pageid=13815
I've not seen anything in the guidance material about PSC and can't help there so you may need to talk to a local AME.