That’s a great startup pitch ;) I think they got 1.5million in funding too!
There’s not very much info about Simplex. It looks like they act like a 3rd party (high risk) by guaranteeing the funds (by simply paying upfront the bill). And I think they only deal with verified accounts and this is only on a few btc exchanges, btc wallets, mining pools
here, *so doesn't apply to the OP specific question of On site purchase.
Here’s another good source
Bitcoin wiki
I think all the above (companies from the wiki) still require some sort of KYC verifications (uploading ID) or that the purchases are made via a paypal or western union or have certain limitations – at least for North Americans (maybe in EU its different),
Bittylicious is a good example .
I mean in the US all purchases at a btc ATM require ID and a Hand scan ;)