We (think) we solved it using Easy Data Transform (including some judicious use of Javascript transforms). Can you solve it, with or without Easy Data Transform?

We will publish our .transform file after the official results are announced.

Please Do Not publish solutions or answers here until the answers are published by GCHQ, sometime on Friday. Any answers published before then will be deleted - we don’t want to help cheats!

Looked at this a bit more and we have used EDT to find the possible combinations of values of all the digits. But a bit more is required before fully solving the problem. So we have got at least part way to a solution!

Cool. It is a competition aimed mainly at (smart!) 12-18 year old children. I don’t want them to be able to find the answers by searching online. Not on our forum, anyway.

I loaded the transformation, on Mac (M2, Ventura 13.6.2) with 10GB Memory assigned to EDT it shows after a short moment in the cross transformation 84% Memory used of the 10GB and crashes afterwards. This happen everytime.

Another try: With 20GB it does work, but runs for “long” time.