I’m in the process of changing a panel van into a Kombi van. On fitting the lashing points I’ve found that two of the points don’t have captive nuts. Just a hole and a bung. I will be fitting a Kombi style bed to the points so I need to sort both of them out. Before I take off the trays/trims, can I buy the required the captive nuts or shall I just use a standard washer/nut?