Obviously a printed surname certificate needs to be printed on something!  Plain white paper will do, but it's possible to buy pre-printed paper which is made by a company called "Deca Dry".

I ended up getting mine from my local stationers and from the local hobby/craft shop.  I'm also going to order in some specialist paper from the USA.

For now though, I have some marbled effect A4 paper, a bit like this:

And some printed scroll paper a bit like this:

Which is enough to at least get the site started!