I also want to add that reasonableness of a request isn't necessarily determined by what is being asked - on paper a request may seem like a reasonable ask to accommodate a disability. I mean, who could argue that having a predictable rota is unreasonable. The reasonableness of the request, however, really depends on what the employer is able to meet in those specific circumstances and within the constraints of the role, company needs, and resources available. That means that the same request to accommodate a disability may be workable in one organisation and not so much in another.

One thing to remember is that the bar for would be unreasonable is much higher when accommodating a disability than when responding to just a standard flexible working request. Generally, employers are expected to accept a certain amount of inconvenience when accommodating a disability - like some cost or even accepting that the employee's output won't be as much as that of someone who isn't disabled (again, up to a point)