to ask about a wedding gift for a couple who have it all

[Mayflower2017]

Hello mumsnet ladies,
We've been invited to DH boss's wedding.
It's a second marriage, the couple in late 50s. They've lived together for years, have a huge beautiful house, holiday home, yacht, multiple high end cars, you name it - they have it all.
Question is - what do we get them as a wedding gift? What is acceptable for people like that? We are not hard up but we don't mingle in their circles either (we are in our 30s).
Would be nice to get something thoughtful/personalised but cannot think what.
Your suggestions/ideas are much appreciated.

I'd probably just give a bottle of nice champagne but it's not that original.

What is your budget? For people like these, I find a Fortnum hamper goes down well or a very expensive champagne or wine. If they have everything, they won’t be looking for keepsake or another oven dish.

Possibly a gift voucher for a meal wherever they hold their wedding and possibly a message saying it’s for a 6 month “anniversary” meal to remind them of their beautiful day

One gift we received which I absolutely treasure was a small watercolour of the castle we held the wedding in.

I don't think it cost too much as my friend said she got it from sending in a photograph to a lady on Etsy.

How about you each give them a really nice edition of your favourite book, with a dedication explaining it?

Thank you

People like that can usually find somewhere to put a silver photo frame...

A canvas/painting/aerial photo of their wedding venue.

The constellation of the date of their wedding.

notonthehighstreet website have a lot of personalised wedding gifts

I have previously brought people trees for their wedding. Both an actual tree for them to plant, and sponsoring a tree via a charity, which they can go and visit. (this was for walkers, though).

A charity donation is also nice, esp if they have reason to care for one.