p.p.s!! When you complete your application the system will work out that you need to submit a PC (based, presumably, on time spent in Singapore since receiving your PR). I suggest writing a letter describing exactly as you did above that you require a letter from Home Affairs requesting a PC in order to proceed with an application for the PC and upload your letter under the heading provided when you conclude your online application "CHARACTER- EVIDENCE OF (SINGAPORE)". This will hopefully make more sense once you get to upload your documents Good luck!