The only thing I can think to do is simulate a system using wire loops and test it that way. 

 

If opening zone 2 triggers the other zones I know it's panel or programming.

 

But having 2 dodgy panels is almost impossible I think.

 

I'm stuck

The only thing I can think to do is simulate a system using wire loops and test it that way. 

 

If opening zone 2 triggers the other zones I know it's panel or programming.

 

But having 2 dodgy panels is almost impossible I think.

agree with all of that.

I'm not missing a really obvious bit of progarmming at start up or something am I?  Or programming in another way than the default Programme 1?

 

I checked the setting on each zone and it was definitely 1 timed, 2 inhibit, 3-8 immediate.

No it isn't programming. Out of the box it wouldn't do what ur reporting. Prove the panel by disconnecting everything then once proved add things one at a time. One option would be to wire the rear door onto 2 and link 3 and follow the same process if you don't want to strip all the wiring

Well - will report back as will be spending tomorrow trying to fix this