Ryanair No-Show letter

We were supposed to travel to Faro with Ryanair last week but in light of the current travel restrictions and self isolation requirements it wasn't possible for us to go.
I have spoken to my travel insurance company and they are requesting a no-show letter from Ryanair confirming we didn't use the flight.

The only thing regarding this I can find on the Ryanair website says to request it via the live ChatBot, but after trying many times it doesn't seem to understand my request. It also gives me the option to ring customer services but I had that experience recently and it took nearly 90 minutes of holding to get through.

Any information online from other websites seems to be very outdated, mostly from 8-10 years ago.

Has anyone been though this process recently and successfully got the letter? How did you do it?
In typical Ryanair fashion I presume there is an administration fee for it, although I haven't seen it mentioned anywhere.