Thank you mbmoffat for the quick reply. I went to log on to HMRC and because it was so long since I'd done that I had to start over with new passwords etc. Well with all the security checks I also had to download the Gov.uk ID app and after several attempts it did work using my BRP card and face scan picture. Thanks for the clear explanation of how to find the Tax Year Overview, I found them and printed out three years worth. Good suggestion about having the accountant write a letter explaining things.
For the Referee letters, I will get my photo done tomorrow. Then when my friend returns from India I'll get her signature first and drive to get my second referees signature soon after. THEN I'll continue with the online application. I guess that makes sense?