There is a lot of FUD spread by (many) software companies about filing online and that you must have some kind of (ie. their) special software. They are using the oldest marketing trick in the book, fear.
Here’s the reality. There is no law that says you must use software. Until there is, neither HMRC or any other Inland Revenue service can force you to use software to file (or even do) your accounts using a computer. In the UK the majority of accounts are still done on a spreadsheet (last time we did a survey it was around 50%, but as software gets easier that figure will be declining). So, will Microsoft (et al) suddenly release a UK specific HMRC uploader for Excel? Not anytime this side of the next millenium!
When HMRC and other Revenue services say you MUST file online by such and such a date, all they are saying is that you need a computer (your library has one if you don’t) to log in and enter your data via a computer by hand. What they are stopping is the paper format, that is all.
Does anyone remember when HMRC said you could have a tax refund if you filed your PAYE online a few years ago? What happened, some software companies started claiming that if you bought their software you would get a massive rebate (as though it was courtesy of them). They pushed the same FUD that you needed special software to file online too! What a cheek.
Maybe I am cynical, but if there is one thing I have learnt about corporates it is that their marketing departments are kept as far away as possible from development (and reality).