"GB" it most likely was 350 gee gee's a side but for some reason I recall 425 gee gee's & the stubby 4 blade props. DP (The owner) said it would cruise with a high power setting right up against VMO, didn't see it but I believed it the way it took off heading for the Moon!:-)
"TTY" that's very interesting indeed, I recall coming in to work the following morning to see it's back broken around the main cabin door & sitting on it's 4 blade props..............looked like it was a dead duck!:-(
"DR O" sure was the one:-(
Wmk2