How to check previous years' self employed tax?

I'm a self employed sole trader with a pretty standard type of accounts. I want to check the work my accountant has done. Is there a site to check self employed tax for the previous few years? - with detailed information about rates and allowances etc. I've found several free calculators but they are very simple and they don't give rates, allowances and such like and also they don't take account of age and pension income. I found an HMRC site for employed income, but not for self-employed. Have I hopefully just not yet found the HMRC site? If not, then any other suggestionsP Many thanks.

Hi,
You can view the personal allowance and tax bands here:
Income Tax rates and Personal Allowances
Thank you.

This is not useful. It is not what I want. What I am looking for is a calculator which I can put my raw numbers into and it will output the correct tax. The page you point to would mean I have to make a spreadsheet and I don't want to have to make a spreadsheet because it is work to do that and I might get it wrong. For example, that page doesn't say anything about national insurance. If I knew enough to make a spreadsheet, I wouldn't need to be checking things. There is an actual calculator for employed income, is there not also for self-employed?

Hi, See link below:
HMRC tools and calculators
Thank you.

This is no use. It only applies to the current year, but what I want to do is to check previous years. Where can I check previous years please?

Hi,Your Self Assessment calculations for previous years show in detail the rates applied by our systems to all income declared - if you would like copies of these calculations and cannot access them via your Personal Tax Account or accountant, contact us by webchat or phone via:
Self Assessment: general enquiries 
If you still wish to calculate this yourself, the calculator previously provided should provide largely accurate results. Alternatively, you can calculate your tax bill yourself using the rates and tables provided, use a 3rd party calculator, or employ another accountant.
Thank you.