I agree with you Fitter2, it certainly wasn't the nicest handling glider I have flown but it wasn't the dog that some make it out to be.
I once flew one in a formation display at an airshow as number two; the leader was in a Bocian. I think from memory the book numbers showed that the T53 had an edge in glide ratio and sink rate, but our two were virtually identical.
I had forgotten about the "bonk" noise.