You might not get an official response from Koinly as they seem rather busy at the moment. However as a UK based user I can confirm that it does calculate the same day and 30 day BNB rules correctly. You do have to change two default settings for calculation to be correct (From my under standing of reading HMRC guidance) (Turn wallet based cost tracking off and treat Airdrops as income off). It would be nice if these settings defaulted to the correct place and it gave you a warning if you changed them.
Before I switched to Koinly I was using Accointing but that company defiantly does not calculate tax using the UK 30 day and same day rule so had to find another provider.
Koinly presence on this site has been rather lacking recently (hopefully it just due to the US tax dead line approaching so they are busy supporting paying customers).
For me the software works well and I hope nothing bad is happening behind the scenes but I have kept a back up of all my transactions just in case I’m forced to find another provider in future