Submitting my tax return take 2

For some reason it's asking me to fill in some fields:

Some fields have been prepopulated with information they already have, such as my date of birth. However, they've prepopulated it with a format which is not compatible with their own system so I'm forced to amend this myself:

The date entered for 'Date of birth' is in an incorrect format. Dates must be entered in the format dd/mm/yyyy. Please amend.
The date entered for 'Date of birth' must be on or after 01-01-1851. Please amend.

The message above demonstrates that this hasn't been properly tested. It's not great practice to use multiple date formats in the error messages.

Annoyingly the IR have changed the form again, so it has taken me a lot longer than I had hoped. I know they're trying to make it easier, but changing it every year doesn't help those who rely on using a template based on the the previous year's.

Anyway, I've filled it in and I owe the IR lots of money, mainly due to rental income for the house I own. I'd been doing repairs on it over the last few years which were offsettable expenses, but now that I'm doing much less, the tax bill is so much greater. Also, they seem to have introduced a payment "on account" scheme (see http://www.hmrc.gov.uk/sa/understand-statement.htm) whereby they take next year's tax in advance. They predict this based on what this year's tax was.

Anyway... I've put calender reminders in outlook to ensure I don't forget to pay like I did last year, as I'd rather not pay the £90 fine again. They craftily *don't* remind you as you get closer to the date. A cynic might think that they are hoping that you forget in order to administer the charge.

Just clicked "submit" and yes, you guess it...

Sorry the system is unavailable, please try again later or contact the Online Services Helpdesk.
Quoting Ref No: B6U4S7FPVR. Please select 'Next' to proceed.

A cynic might think that they want me to forget to submit it at all, which nets them a further £100 plus interest fine.

I'll try again next week.

11 November: same error. I call the help line, which is impressively open until 8pm and Siobhan says that they're aware of the problem and instructs me to delete my internet files and my cookies. I try again but it still doesn't work. Just to be sure, I try using FireFox instead of IE but it still doesn't work. She tells me that they haven't been given a timescale for a fix, but I should try again 'later'.