What are you really asking?
Yes, an in service military jet would be able to perform an inverted flypast within the parameters of the display conditions.
No, any F-104 flying would not be able to perform an inverted flypast at an airshow in the UK as of today as it would be civilian owned.
The Belgian Air Force F-104 team were nothing to do with Diablo Rouges who flew Magisters, they were called the Slivers and by all accounts flew much lower than what is permitted today, so yes they would have to change their routine to suit the rules.
As for the picture, not one of your best.
