Thanks for your reply.
More information we have found one this:
The Order number issue actually seem to be with the UserID segment which being a guest user is set to -1. This makes the order number 00--0001-12345-12022014. The extra hyphen from the -1 seems to be causing the issue with the Order number on our orders screen. I have checked the code and there does seem to be a check which should convert it to 0 but this doesn't seem to be working.
The IPN however is still now working, would the UserID being -1 cause an issue here as well?
More information we have found one this:
The Order number issue actually seem to be with the UserID segment which being a guest user is set to -1. This makes the order number 00--0001-12345-12022014. The extra hyphen from the -1 seems to be causing the issue with the Order number on our orders screen. I have checked the code and there does seem to be a check which should convert it to 0 but this doesn't seem to be working.
The IPN however is still now working, would the UserID being -1 cause an issue here as well?