Paul, the 30 minute wait sounds about right for the "alarm reset" from a failed access attempt.  Do you have the EKA?  If so this can assist here as I think it will override the alarm's waiting period.  But even so you are going to need 12V at the battery to ensure a start.
Best solution would be to get hold of another battery, drop it in, wait half an hour and try and start it.
				
			 
			
		 
			
				
			
			
				MY15 Discovery 4 SE SDV6
Past: 97 D1 Tdi, 03 D2a Td5, 08 Kimberley Kamper, 08 Defender 110 TDCi, 99 Defender 110 300Tdi[/SIZE]
			
			
		 
	
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