Rolled-up interest vs retained (discounted) interest: what a £100,000, six-month loan really costs

https://echo-wiki.win/index.php/How_to_stop_hidden_exit_fees_wrecking_fast_property_finance_in_the_UK

You’re offered a six-month facility tied to a £100,000 face value and told the interest is £10,000. Sounds straightforward