My first inclination would be one large plate glass mirror with the lights mounted over it. If you are set on three mirrors it will be custom, but a good glass shop could make a beveled mirror in a custom size. If you really want a wood frame buy trim from your vanity manufacture and use it to frame a custom mirror or buy a frame from pictureframes.com and then get mirror cut to fit.

I posted a few days ago on the thread "Biggest Lesson you learned remodeling a bathroom"..."get your mirrors first, or they will have to be custom!"

Find a craftsmen (your cabinetmaker?) who can make the frames for you.

Then find a custom glass store - they usually also cut custom mirror sizes.

Looks like we were all posting at the same time!

Tagging onto Ellsworth's comment, I'd go with doing a full, countertop to ceiling glass installation on the full wall, then getting a carpenter to stain and trim it out with a wooden frame. Going to the ceiling would require you cut holes in the glass for your light fixtures so the plate goes on top of the glass. If that's too complicated for you, simply make the height of the mirror lower (or less wide, depending on where you're placing your fixtures above the mirror or on the sides). See examples:

Thank you everyone for your helpful advice I do have a question now about the one large mirror when your seated at the makeup desk won't you be looking directly at the frame this is my concern about how do you drop down

the mirror to make practical and eye appealing this is a tricky request lol ))

John, the frame size doesn't have to be as wide as the ones shown here. Your glass guy/framer could advise you more specifically since we're commenting without the benefit of photos of your space.

Thank you for your advice I have the vanities but is not mounted yet I'm not at that stage yet just thought I would try to get mirrors ordered but I agree I think this is a custom fitting as finding pre built is a needle in haystack

thank you everyone for helping appreciated greatly

You, or anyone, sitting at the vanity will not be using the wall mirror for makeup or anything requiring a close up look in the mirror. Hair, maybe, but you should be able to see your hair when seated. Most vanity tables have a make up mirror sitting on them. So you can just do something like this:

or with 3 mirrors the same size and a table top mirror:

Or think outside the box:

This is why I design bathrooms with all the same height counter and you sit on a stool to do make up which BTW is more comfortable too.

What's your suggestion, Patricia, for the OP who already has the bathroom built differently than you would have done?

Various ways of doing this, the lighting set up affects these choices. How will that be or can you do it according to your final mirror choice?