When there is a transfer of ownership of the invoice (i.e. a "sale" of the invoice), then by definition the transaction must be factoring, not invoice discounting. Invoice discounting is a type of loan/financing that does not involve a transfer of title. The only exception in the world is the UK, where invoice discounting/financing is basically the same thing as factoring. Here is a quote from Wikipedia https://en.wikipedia.org/wiki/Factoring_(finance)#Reserve_account:

Factoring is the sale of receivables, whereas invoice discounting is a borrowing that involves the use of the accounts receivable assets as collateral for the loan. However, in some other markets, such as the UK, invoice discounting is considered to be a form of factoring, involving the "assignment of receivables", that is included in official factoring statistics. It is therefore also not considered to be borrowing in the UK. In the UK the arrangement is usually confidential in that the debtor is not notified of the assignment of the receivable and the seller of the receivable collects the debt on behalf of the factor.

Now if you tell me that Populous is going to focus only on the UK market, which represents less than 4% of global GDP, then the transaction steps they've outlined make sense. In the rest of the world, which encompasses more than 90% of the global opportunity, the transaction as described by Populous will not work. In the USA for instance, non-notification factoring represents only 12% of the total pie, and is only available to larger companies under long term contracts and based on a pool of receivables (never one-off transactions). In addition, the due diligence that invoice sellers are put through under non-notification/confidential factoring is akin to bank lending; it's thorough and complex, thereby expensive to do.

The way that Populous imagines these transactions is completely ridiculous, and provides no protection for the invoice buyers. You mentioned that under the Populous model, the sellers will pledge corporate assets while company directors are to give personal guarantees... do you really think that Populous will pay the costs involved in international litigation to recover against sellers based outside of the UK? I doubt they will do that even inside the UK, as enforcement of these types of pledges is very expensive from a legal standpoint, and wouldn't work for any facility of less than $150,000-200,000. Again, for these transactions to work, the buyer of the invoices needs to take control of the repayment from the ultimate customer. Under Populous' current model, there isn't even a notification mechanism for the invoice buyer to be informed when the invoices have been cashed out... how then is the buyer supposed to know whether non-repayment is caused by debtor default (so that credit insurance can be invoked) or by the seller's non-compliance (so that legal action can be taken against the pledges) It makes zero sense.