Ruud van Nistelrooy’s interim spell as Man Utd manager is finished but his time at Old Trafford remains under a cloud of uncertainty. Van Nistelrooy hasn’t done anything to harm his long-term prospects and if anything, he might have done a bit too well for Ruben Amorim to keep him as an assistant in the background! The legend, however, has made no secret of the fact that he wants to stay but is fully aware of how his spectre can loom large. It did over Erik ten Hag and Amorim might be wary of doing the same which won’t be helped by Van Nistelrooy winning over everyone as the main man in just f…