Thanks for the heads up. The files concerned are .ts files of recordings.
When I no longer need the recording after viewing it I delete it using OpenWebif
But I then had habit of emptying the trash can on a regular basis, also via OpenWebif. Emptying the "Rubbish bin" is normal practice in Linux Mint for example.
I access the sat tuner remotely hence the use of OpenWebif, works very well (timer programming, downloading recordings, deleting them. etc).
But over a few months I noticed I had lost about 100GB capacity from a 250GB HDD and even one fouled up recording, a reboot cleaned things up.
My current setup is "Remove from trash after 8 days" and "Keep 40GB for recordings".
But from your comments it seems the best approach is to let enigma take care of trash management.