What mobile number did you use when you registered with Clickatell? That number is the one (I think) they use as the sender ID. If you used a UK number (I'm not sure why you'd do that) then that's why this is happening. In FrontlineSMS you can set the Sender ID in the settings (see the "Help" files for more information) but you have to have that number registered and approved by Clickatell before you can use it.
If you're doing all this correctly then we'll have to take a look - there could be a bug in the software but this hasn't been reported before.
Let us know if you have any luck.
Do you know whose UK number this is? Does it belong to Clickatell, or is it random? Sounds extremely strange.
If you can have a look and let us know, we'll investigate if you find nothing. Maybe Google the UK number and see if it shows as belonging to anyone?
Okay, can you send another couple of messages and then submit your log files? (You can do this through the "Help" menu - you won't see an "In progress" message so give it a couple of minutes to confirm the logs have been sent before doing anything). We'll take a look at those and see what's happening.
If nothing has changed at the FrontlineSMS end then all I can think is that this is something happening at the Clickatell side of things. We'll get back to you as soon as we can once you confirm you've sent the logs.
I have sent the logs through.
Thanks very much for sending through your logs. Our lead developer, Alex, has taken a look and has advised that this could potentially be a problem on Clickatell's side. Just to check/ confirm, when Clickatell did some tests on this did they also experience the same problem with your sender ID?
The other possibility is that there is an error in the format of your settings, but we will need to do some further testing our side to see if this is the case, and will get back to you with further information as soon as possible.
In the mean time, please do keep us updated if you make any progress with this!