Comment by drstewart

So all these commercial software offerings for SAs exist just for fun? I guess I just don't understand why these exist. Europeans have yet to explain this adequately.

Can you show me the free option that existed in HMRC's portal for non-domiciled statuses? I can only find websites that contradict your point:

https://www.dtaxfiler.co.uk/blog/residence-remittance-sa109

>You will need to use commercial software that supports the SA109 form (such as DTax Filer), You cannot submit the SA109 form through HMRC’s free online service. . If you do not use compatible software, you will need to print and post your tax return instead.

Clearly they're lying and you should correct them post-haste.