Although it would have been helpful for the organisation to let you know of specific adjustments, or suggestions for adjustments that they would or could offer in advance of the interview, we do not think they were legally obliged to do so.
With that being said, the organisation may have been under a duty to make other adjustments to further reduce any disadvantage you experienced as a result of your diagnosis. This could include having given you the questions in advance. The question is not whether they should have given you a menu of adjustments but rather, whether they took sufficient steps to avoid any disadvantage that you may have experienced, when compared to other non-disabled candidates.
This question is fact-sensitive and much will turn on the nature of your diagnosis. The prospective employer may, for example, argue that they did fulfil their duty to avoid the disadvantage by allowing you to have the questions written in front of you whilst you answered.
If you are considering making a claim or taking any further steps we would suggest getting legal advice as soon as possible. You can find out more about where you can get this advice here.
Following this experience, perhaps think about keeping note of the adjustments that would be helpful for you, so that you can be ready to ask for these in advance of your next interview. Seeing the questions in advance is only one suggestion, you will need to think about what will work for you. It may be that your adjustment request will not be the same for every interview, but will depend on the organisation or role that you are applying for and the recruitment process.
Our section on applying for work has more information on telling an employer that you are autistic.
Employers and work providers also have duties when an applicant or employee discloses that they are autistic, and when recruiting and managing autistic employees.
Our Resources section has more information about services offering legal advice on employment matters.