Self Assessment Tax

I work for a foreign government embassy in the UK, and I have to file my own tax and national insurance from the salary I receive, as foreign government offices in the UK do not come under preview of local law in the UK. The self-assessment form on HMRC is too long and contains questions that are not relevant to the job. Earlier it used to be a short form, and now I feel it is too confusing and not easy to fill out. Also, I would like to know if there is any software that would make it easier. Many thanks

Hi,
For guidance please refer to the link below:
Self Assessment commercial software suppliers
Thank you