I have a Skywatcher 200P & EQ5 and mine did have a T Mount as standard. The 1.25" adaptor is screwed into it. The EOS adaptor will also fit on it and can be left on it. I just have to unscrew the 1.25" adaptor from the T mount to fit my Canon on.

I'll take some pictures tomorrow and post them for you to compare with yours.

Here's the T Mount and 1.25" eyepiece holder taken off the telescope, this is standard without the EOS adaptor fitted. you can see the screw thread below the 1.25" adaptor where the EOS adaptor would screw.



Below is with the EOS adaptor fitted to the 2" T mount, and the 1.25" adaptor unscrewed.



this is the way I normally leave it on the telescope.

Biil,
I think I've twigged it.
Your original Canon adapter with the 48mm thread is designed to screw into the coma corrector which then slides into the 2-inch focuser. Without the coma corrector only the middle 10mm or so would be sharp so the coma corrector is the way to go.
The Canon T-mount (42mm) will be useful for other things but is not required for prime focus imaging with your scope.

Great! I now have options. As you guessed David, the thread on the coma corrector matches the EOS adapter so I'll try that first. If I have focus problems I'll get the camera adapter/nose piece from Pulsar Optical. Thanks all for your help. Anyone know where I can book a clear sky? preferably after dark.

You're right David. The coma corrector has the same 48 mm thread. If I have focus problems I'll try the camera adapter from Astro engineering.