11 year old DS, severe separation anxiety and secondary school struggles - suggestions for alternative London schools?

Agree with the suggestions of a PP regarding school based interventions (and private therapy). Unless there is something about the particular school that is a real trigger for him, you’re better off keeping him where he is and treating the anxiety. (As long as school can provide the support and intervention).

changing schools may add to the unsettledness and also possibly confirm he’s right to have trouble separating. Unlikely a new school will “fix” the issue, particularly if you’re right about the cause being covid and bereavement.

I liked what a PP said about how they communicated through their actions that they knew underneath it all their DS was a capable boy who can learn and make friends. In the long term, this is a v v good message for him to internalise.

if this is the tip of iceberg of more significant MH problems (I don’t feel from your OP that you think it is) then maybe look into therapeutic schools such as Red Balloon etc but I don’t think that should be first step.

Would something like the Red Balloon Centres be an option? I know that they are usually for children who can't go to the usual school because of bullying etc, but it might be suitable for this type of difficulty as well, particularly if the anxiety then develops around what the other kids have seen or what they might think, say etc. I think there is at least one in London.

On a micro level (just one of the issues you mention) I bought my son a towelling robe that you wear and get changed under with some modesty (like what you have for toddlers at the beach). There are heaps for older children / adults now. Game changer!

Portland Place offer a hybrid model with 2 days in school and 3 online, if that could be an option. They are very accommodating of SEN.

Yes my DS has particular anxiety around PE and getting changed. School let him change in a separate room, maybe your DS can do similar?

The relentlessness of it is exhausting and brutal. Especially I find, when he generally comes home feeling much better about things in the afternoon! Everything we were told (and have generally done as a result) has been based on the idea that if you validate the anxiety you only make it worse so you're doing the right thing by persevering. I know not everyone agrees with that approach but we were confident that underneath it all he was kid who loved learning and making friends and that we had to help him access that even if it seemed a bit callous in the moment when he was screaming and begging to come home with me.

Practical things that have helped:

Distraction - we play wordle/globle/nerdle etc on the walk to school, we make up stupid song lyrics, I gossip about grown up stuff I think he'll find interesting, tell jokes, anything to keep him talking and his mind off the impending separation helps. Don't talk about school or try and reassure him, it just makes it worse!
Responsibility: He's given a job by staff (sorting resources, setting up the hall etc) and has to go directly to help that member of staff instead of am registration. Makes him feel needed, breaks the routine.
Time: Letting him go to a safe space and then joining lessons when he's ready
No loitering: Sounds awful but basically, dragging it out only makes it worse. Once they've got hold of him, run away and don't look back. I've actually spoken to my son at length about this and he agrees that it's the best way for us to do it and that he finds it less upsetting overall.

You've basically described my DS12 except his issues started in Yr 5 and he's now Yr8 and we're out the other side of it (though he still has anxiety and finds the morning drop off in particular a difficult transition). What has worked for us fundamentally is CBT and exposure therapy (via CAMHS, though you could look at private support), we've chosen a school with outstanding pastoral care (a local comp with excellent SEN provision) over a more pressured academic environment, and we've accepted that baby steps are big milestones and it'll take him time but he will get there slowly.

I had similar worries to you, but his friendship group and cohort have been hugely understanding and supportive, he's not had his 'weird' behaviour picked on at all. His teachers and support staff all know how best to handle it and can read the room effectively (eg some days he needs distraction, some days he needs a firmer approach, some days he needs to be given time and space to adjust in a separate room).

He is thriving academically despite the anxiety. For my son a lot of it is about getting over the hurdle of getting through the door, if that makes sense? Once he's in he is genuinely ok (I appreciate that's not true of all kids).

If I were you I would give his current school time to come up with a support plan. I would expect them to be offering tailored interventions, planned 121 support (at the gate especially), emotional/social training eg ELSA, something like a zones of regulation programme, to teach him self help skills.

If they can't deliver then look to move him but don't assume that smaller is better. DS is at a very large school with a third of kids with SEN, but that brings with it a huge amount of resource and support.

It is hugely draining having to deal with this as a parent, it has broken me several times so I feel your pain. But it does get better, I promise.

As a teenager the actress, Rebecca Front ( Thick of it), suffered hugely from separation anxiety due to the death of loved ones around her. She came through it but reading an account of her struggles gives you a good understanding of her mindset and will help you understand your son.
Perhaps you could borrow her autobiography, Curious, from the library?
She got through it by the school giving her mother permission to work in the school library for the first few weeks.

Jo at Tayberry Tuition is great with kids who have any kind of anxiety surrounding school, whether they're refusing to go, or just have a lot of anxiety surrounding school. My son was getting quite "worked up" (to put it lightly) about going into school at the end of last year and she really helped managed his anxiety around it and find out the route cause. I'm sure she'd be able to recommend if there's other schools that might be better suited as well X