I'm just wondering, because this isn't the case with any other SMS web provider I use e.g. mobiSMS? I'm guessing it's because of the HTTP POST interface and you need to change the ? into a Unicode character of some kind, but please fix it if possible..

Thank you for raising this issue to our attention. On investigation this is a fault in the way the front end is counting the character requirements. When the message is actually sent the correct number of characters are used.

This issue will be addressed in the next release of the website later this week.