Requesting Morning Dress at Wedding?

I wanted to clarify this for my family, who are flying from abroad and are unfamiliar with Morning Suits. Also, I don't want to ask our evening guests to wear morning suits, so for them, I wanted to add formal suits to the dress code. Is there a way to phrase that so women also know what they need to wear, like the length of dresses and fascinators?

If you want women to wear fascinators or a specific skirt length, then I think you are actually going to have to tell them those things. Morning dress code for men in the UK is quite specific, but for women, it is more general. Hats are optional, and in some situations where morning dress is required, fascinators are not allowed, so they definitely won't be automatically worn as part of morning dress.

As for your family, if the men already have morning suits, they will know what is meant by the dress code, and if they don't, presumably they will be hiring their wedding attire in the UK rather than have to bring it from overseas, so you can always direct them to a suitable suit hire company.

Maybe put something like “Formal morning suits requested: please see website for specifics” on the invitation, and then on your website you can go into as much detail as you need to. If I was a guest I’d appreciate knowing I could get the specific information somewhere, as it’s not a dress code I’m used to (although your guests might be more au fait with it than most!)