Thanks D_R_J, that's encouraging.
In total we have :
Five years living together (two before marriage, three after), with tenancy contracts, joint utility bills, and individual bank account statements for proof.
Sponsor (my wife) as a supplementary card holder on beneficiary's (me) Amex for four years with statements.
Sponsor receiving private health insurance through beneficiary's company as partner of beneficiary
Sponsor listed as work life insurance policy beneficiary for 6 years
Engagement ring invoice from 2020
Hundreds of pictures together in a 30 or 40 page pdf document
Boarding passes, hotel receipts etc. for joint travel over 8 years
Affidavit of support from our mutual very close friend who introduced us
My original thought was just that the immigration official would open a document, for instance the life insurance nomination of beneficiary, and would have to work out what it was and why I'm including it. But I suppose it will be pretty obvious and I'm probably overthinking it. I'll just try and be descriptive with the filenames.
I guess I am just trying to guarantee we get it right first time as it would be so annoying to have the already long process delayed because we don't include something or there is a misunderstanding.
By the way, DCF isn't available to us as they stopped routinely doing through the London Embassy in 2019, and only do it for emergencies now.