After its introduction in 2012, the dress code for Royal Ascot has become well-known for banning fascinators, spaghetti straps, and asking male guests to wear only black or grey top hats. 2015 is no exception to the rule and this year’s style guide has outfit suggestions for guests to wear. Here are some of the top designers that are most likely to be worn at this year’s race meeting:   Gina Foster Hats are a necessity when it comes to Royal Ascot fashion. Gina Foster is a popular alternative to Sir Philip Treacy when it comes to luxury millinery. With a special collection on her online store dedicated to the…