I like the spirit but wouldn't this run afoul of one or two laws? Identity fraud or some such? I'm not in the UK, so I don't have any idea about their laws, but I'd be shocked to find this was above board. Your FAQ claims it's a parody site and claims " The ID number isn't valid and you can't use the card for anything real. " but you've just confirmed here it can indeed be used for real things (discord, reddit). Your…
The only way you'd ever get found out is if the affected MP was lying to the public and the identity documents do indeed get retained...
I'm more talking about the developer of the site rather than the users. And the developer could potentially be found out if they posted it on a popular hacking website and used a known alias and registered the domain in the UK.
But, if they're comfortable, all the more power to them. As I said, I do really like the spirit of the site.