I have recently dug out my old archives of Teenagent to send to scummvm team and while searching the net for disk images I stumbled upon this thread. I don't have disk version of either ECS or AGA release but I manged to compile the game under WinUAE and it seems to work in my old dev environment. I haven't touched 680x0 stuff for more than 10 years so I can't be sure if I removed all stupid checksums even having the sources, but hopefully it works (tried a couple of old saved games and worked fine). If you want to try here is the archive:
http://strony.aster.pl/mokmtg/TeenAgent_Amiga_Exe.rar - it contains 4 executables. Polish ECS & AGA, English ECS & AGA. Yes, replacing the executable is enough to play in english. Simply swap original protected Teenagent executable with one of the 4 (just don't use AGA for ECS version of the game and vice versa). Let me know in case it crashes at some point and I'll try to check the source a bit more carefully
The files are straight from Asmone so not crunched at all... probably won't fit on disk 1 without packing.