Got my new BSI back from RollingMotion auto electricals today, who cloned my original BSI and copied it to a new (used) one, which fixed my A/C issue. He was also able to find out the key code which had been lost before I owned the car, so I though I'd knock up a little template which is based on the real one Peugeot uses. Took me a fair while to trace the key I'll tell ya!
Here is what it looks like using an example code:

And attached to this thread is the .pdn (Paint.net, great free image editor like PhotoShop) template which you are welcome to use and tailor to your own car! Just though it keeps things looking neat and presentable in my leather handbook holder.
Link: http://www.filedropper.com/keycardtemplate
Hope it helps someone

Benjamin