How do I send in certificates?Watch
They don't care enough to chase you up on that. If you have an interview they may well ask about it but what matters is how you relate it to wanting to study the subject
what a flex
Yeah, they most probably won't need to see proof of something like that but for future reference you'd scan them in and send a copy digitally either by uploading to UCAS or via email.
As above, the certs are almost irrelevant, it's your writing about the experiences and they relate to your interest to the subject in your PS which is important.