Legacy ways of purchasing Bitcoin around 2012

Hi friends. I stumbled upon Bitcoin by chance back in 2012 and purchased a small amount. Like most, it wasn’t until many years later that I appreciated it more and the big opportunity I had missed. Fortunately, I did manage to get a small amount for a reduced cost.

At the time I was following some instructions that advised on creating a wallet on blockchain.info, doing a bank transfer and then receiving coin to that wallet.

This was the process I followed and now, I’m trying to build up decent proofs for all purchases. Most of them whether they were the likes of speedybitcoin etc, sent emails out which have helped and I’ve been able to cover them.

This one though… nothing, the only thing I’ve got is the original wallet (I still have the private key) and what is seen on a block explorer. I’ve also tried and failed to get historic bank records.

Does anyone have any ideas on services back then that operated in this way, via a bank transfer and specifically included a guide on how to register a wallet with blockchain.info?