Thanks for coming back to update us. It’s brilliant that you were able to access the Maudsley privately and your ds has regained the weight. It is very common for anxiety to take hold a year before the eating disorder, so this is something, which will need addressing when he is ready.
If he is eating a decent amount of proteins, fats, carbs, fruit / vegetables and fibre, that will be really great for his mental health and physical wellbeing. However, with his anxiety, behaviours and disordered eating, I would be vigilant as I would think him to be at risk of relapse.
As for his behaviours, it sounds as if these may stem from OCD. It is very common to get OCD when you’re in recovery. And it may well be that he needs to put on more weight. The starting point (presuming there was no disordered behaviour prior) plus 10% isn’t uncommon.
If you are able, I would advise you to talk to the Maudsley consultant yourself for advice on how to tackle the ongoing issues. If you’d prefer to talk to someone else, there are details on the resources thread of people to contact. Dieticians and eating disorder coaches.
We use a very experienced coach for dd and she’s taught me everything I know about ED. She worked in ED for 20 years (in patient) and over 10 years as a coach for mental health and ED, so would be able to help you to address your ds’s behaviours. If you’re interested she’s https://share.google/R1Q5fpGF3VIuvlYYT (this brings you to information on Flourish holistic coaching, Preston btw). She works with dh and me, not dd. Rather like your ds, she wouldn’t engage. We don’t live locally. It’s all done on zoom.