You can self-refer to the Work and Health Programme, you don't even have to be claiming benefits, just ask at a Jobcentre.
https://www.gov.uk/work-health-programme
But I'm not sure that it is what you are looking for at all, and think it may probably not be suitable for you if you have problems engaging with others.
The WHP is fairly new so there are not many reports about it yet, indeed I don't think there are many on it other than long-term jobseekers who have been mandated (forced) to do it.
It's a two-year course, just like the old Work Programme that it replaced.
If it's anything like the old Work Programme (which it seems to be) then I'd say don't touch it because it would not be suitable for you at all.
I don't know about the SES but that seems to be more like the Access to Work scheme, much more intensive than what you are looking for.
https://www.gov.uk/specialist-employability-support
I think that what may suit you best at this stage is volunteer work, and as you can't easily get out then volunteer work from home.
There are several websites where you could look for this type of work, here's just a few:
https://www.operationwarm.org/blog/2...-do-from-home/
https://www.saga.co.uk/magazine/mone...lunteer-online
https://blogs.volunteermatch.org/eng...eer-from-home/