Thank you, Dominique, for your prompt answer.
Your solution seemed right so I took the steps to disable TAUS and somthing called MyMemory, both by Kilgray. [you disabled something else, not the EuroTermBank plugin]
Unfortunately, the EuroTermBank plugin isn't in the list for me to disable. [it's under the "Terminology plugins" tab!] (I thought it might be TAUS, but...no changes in TM behaviour after disabling.)
I don't know how to show you, as you've done, but I can tell you everything that can be disabled in the TM plug-ins options has been disabled...and the absurdly non-native English terms continue to pop up in my translation.
Any other ideas?
(1) Under "Terminology plugins", you can disable "EuroTermBank plugin"
(2) Under "TM plugins", you can disable "MyMemory plugin" + "TAUS Plugin"
[Edited at 2015-06-12 18:11 GMT]