Does this actually mean anything tangible that you can check?

e.g.  had a door recently fitted that is meant to be secured by design but the cylinders are crappy ones that don’t even have anti snap break in them.

I don’t think the standard is overly strict, the description it gives us:

The test is designed to mimic an attack by an opportunistic burglar, using tools which are easy to conceal.

If you go on their website it lists all the British Standards that apply and these will have all the technical detail in, but you’ll probably have to pay to access them.

You should have got a BSI Kitemark cert with the door that shows exactly how it complies with BS 4873/PAS24 (“secure by design”) with descriptions, hardware etc.  It’s mainly just a bunch of hardware numbers though with a brief description, but you can compare to what you had fitted to ensure it is the same. There’s nothing really tangible other than that..