Don't want to derail but did your DS manage to resolve the situation with encopresis
@feellikeanalien hmmm.... yes and no.
He is on daily Movicol which is going to be a long term feature for him as it keeps everything soft and helps promote a bit of regularity.
His main problem is withholding which then makes it difficult to eventually go so then he dreads going and holds it even more so would reach a point of either impactation or involuntarily soiling, on top of the overflow leakage going on several times a day. The withholding deadens the nerve endings which reduces the urge to go and coupled with a restriced diet due to food aversion, it makes it a whole vicious cycle.
The main thing that has helped, aside from the Movicol, has been a toilet routine. Three times a day we take him to sit on the toilet with his iPad for 5-10 minutes. The iPad isn't essential but helps with the encouragement to sit. The idea isn't to go, just to sit to help break that anxiety association but all the better if shit does happen.
We also learned the signs that he needs to go but is putting it off. For him this is behaviours like frequent weeing (from the pressure being put on his bladder), very smelly wind, refusal of all food, repeatedly crouching down and curling over into a ball. When we see any combination of these we know to up his Movicol dosage (he can have up to eight sachets a day if needed but we usually start off by increasing him from one to two and gradually increase it higher as required) and encourage some extra sit on the toilet sessions.
We're in a stable period right now where we've had minimal accidents and he's adhering to the toileting plan but if he goes through any periods of anxiety or illness or upset then it all goes completely to pot and we have to start over. I'm hoping the older he gets, the longer the stable periods will be.
The ERIC website has some really good advice and information, your GP should also be able to help.