Online filing SA....can't so by 31/1/12
If you try to file SA online today you need a gov id signon...which means the 31/1/12 passes while you wait for a letter with password on it. Does that mean the fine doesn't apply since you've tried to file???
Or better
An ex-client rang me about something the other day and said he'd rung up to get his ID underway and been told that there'd be an extension to Feb 15 for him, so long as he paid the appropriate amount of tax by 31 Jan. Too busy to do much more than raise an eyebrow at that, but you could give it a go. And they'll be open for business over the weekend with quieter phone lines I suspect.
You had 300 days to sort yourself out
You will get little sympathy here or at HMRC if you left it to the last minute.
Most accountants can file online as your agent but will have to charge a fee.
You should have got it before
You don't get a fine or interest charged if you submit online by 02/02/12 - no more no less.