I shall probably try dairy free for a few days to see but the thing is I really don't think it is the actual constipation that is the problem iyswim. This latest lapse is typical.
Starts wetting around 50/50 but doing normal daily poo no problem on toilet.
Starts witholding wee and having big wetting incidents in the middle of the day. Goes for wees when naked on toilet morning and night while getting dressed/getting undressed. Poo ok.
Starts doing poos in pants too but still normal poos.
Starts witholding poo which leads to constipation. Except that by now we know the signs well enogh so have not let it get to constipation level as we've just stuffed some fibrogel into him and out it comes. We don't use things like lactulose, it doesn't help at all but fibrogel makes it nice and bulky so he canb't keep it in, it has to come out!
I assume there must be something that triggers him and then it spirals but I'm at a loss as to what it might be.