Yes, I had one once came in for 'help with his Self assessment form" on Jan 30th...came in, sat down, dropped blank form in front of me along with a big tupperware box full of scrunched up receipts " can you do this " says he, I turn over form and explain that SELF ASSESSMENT means you assess yourself and I can only help him if he adds all the receipts up himSELF ...not happy.
You can get an accounts book which you fill in your various expenses and incomings each week ( week per page) and carry forward the totals each week then on the last page - week 52 - you carry everything forward onto a copy of that years SA form with everything in the right boxes so all you then need to do is copy the figures into the same boxes on your tax form.
The worst thing was Accountants, they loved bringing in bundles of completed form from clients JUST before the deadline. Worse of all were the accountants who's clients had completed the forms weeks before but they failed to get the forms in on time costing the clients a penalty charge.......what fun......I don't miss it...