There is a scam called 'authorised push payment' where customers are persuaded to transfer money to a scammer, thinking they were transferring it to a reputable business, such as a [conveyancing solicitor](https://www.theguardian.com/money/2020/feb/29/bank-scam-solicitors-email-hacked).

[Which](https://www.which.co.uk/consumer-rights/advice/what-to-do-if-you-re-the-victim-of-a-bank-transfer-app-scam-aED6A0l529rc) have a page about it, but its instructions for avoiding this are very general (like "Take care"). Is it possible to define a set of concrete actions that you can perform to ensure the bank details you have been given are actually those of the organisation you think it is?

There are 2 situations that this is relevant to me:

The first I suspect is me being paranoid. I wanted a savings account, went to [money saving expert](https://www.moneysavingexpert.com/), picked a [high interest option that I had not heard of](https://www.marcus.co.uk/), and opened an account. About the same time I read that their [certificate issuer was hacked](https://www.theregister.com/2020/05/05/salt_vuln_digicert/), and as I was not aware of any other way to validate the credentials they provided online I was too frightened to transfer any money into the account.

The second is much more like the sort of thing that generates these scams. I am looking at buying property by auction. The auction website has a registration/login process, but appears to be pure http, I have not found a https page. I have had emails from the auction house, and they have no encryption but are sent from a SPF permitted IP address. The property is currently owned by a company with no web presence or telephone number available online, but exists on companies house. If I win the auction, I will have 24 hours to transfer 10% and 20 days to transfer the rest. I expect to get the payment details by email.

In cases such as this, is there a set of actions that an individual can take to ensure that any set of payment information is who they think it is, and safe to send a large amount of money to?