had this problem with mine. turned out to be a faulty glow plug relay. very cheap to replace if this is the problem. if you have a friend or neighbour with the same van you could always borrow their relay to see if this is the fault.
Got the cold start issue with mine. Turns over fine but no fire. So each cold morning I have to undo the air intake and spray some 'East Start' in and hey presto. Been told this points at the glow plugs but any advice always well received.