Whilst I wouldn't use the word EASY, I would say that its pretty straightforward.
I have done dps since the online thing came in and since being self employed myself the last 2 years I've done mine too.
As long as you keep all receipts and figures you will be fine. You can ring the help desk number on the tax return reminders or HMRC website and they are sooooo patient, will advise you on just anything. If you ring up at a quiet time they will go through every box and entry with you and advise what should go in that.
at the end of it when you've put all your income and expenses in, it instantly calculates how much tax and ni you need to pay, and you can go and pay online straight away. Thats what we do.
Oh, there is a bit of faff where you have to get the accountant removed as your appointed representative to do the online stuff (its very secure) and you won't be able to ask any specific questions about his tax or tax return without him giving permission in writing (I think, or giving permission in some prescribed form) to HMRC.
I do have an HNC in business studies from donkeys years ago though so perhaps I find it more straightforward/less frightening than a lot of others might?
DP used to provide an accountant with all the figures, then the bloody accountant charged him £250 + vat just for filling the tax return online!
However, we are just self employed and not earning a lot. Once you go into higher tax bracket or you have employees, premises, importing or anything then I personally would use an accountant and get the best accountant I can afford.
For now its just money in, receipts for bits of things purchased, car expenses and thats about it.
Before dp moved in, when we had completely separate finances I used to make him give me the £250 instead of the accountant