I just submitted last year's (2023/24) self assessment and the process was even easier than the year before. There is a test submission facility that gives feedback from HMRC, there was an error today but support was quick (within 30mins) and effective, the next test was fine then I did the real submission successfully. This process used to take me hours,this App on my phone allows mileage tracking and links easily with bank accounts and credit card accounts. Invoices are easy, logo can be incorporated in the design, I just have a few customers who are cautious in using it. Well worth the money.