When I unlock disco2 I have to start the vehicle with in 30 second or I have to use the unlock again in order to start. Is this normal

 

No, not normal. Nor do I recall a setting in the BCU to program that.

 

That is strangely not normal.
Welcome to the forum.

 

I wonder if someone might've installed some aftermarket, secondary security system that has a timer incorporated.

Is your keyless entry transmitter the stock style for a DII? How long have you owned the truck?

 

Have you tried opening a door other than the driver's door to see if that affects the timeout?
I'm wondering if a sensor switch on the driver's door is not letting the alarm system know that the door has been opened.

 

This is a problem with your passive immobiliser. Using a Nanocom, you go into the alarm settings and disable passive immobiliser. Then once unlocked it stays active to start again until locked.

Can't believe this was such a simple step that nobody (I searched Google also) had the answer too. A local 2nd hand spares shop was able to tell me this immediately when I asked... :P

 

Thanks for digging into this one Doug