Just had the same problem, sadly you can't get away from using number 1 as that's what you enter to set the system...ie 1 # code. Now discontinued try ebay...there is one currently for sale with the end station for £30
downtoearth
May 2010
Persevere and change your code to get away from the '1', otherwise it's a new panel and that one is no longer available.
If you're stuck with how to do this, post HERE again and I'll give you the instructions.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home alarm systems.