GPS Course & Popped Door

I was lucky enough to get another ride in the duchess, this time back seating on circuits, again I can't say enough how helpful this is. If for no other reason than to see that other people make the same mistakes, and to take it a little easier on yourself.
It was a hot day, with full tanks and 3 decent sized bodies, it didn't leave a lot of room on the w & b. The wind was gusting to 18kt of crosswind and although the duchess is limited to 25kts, we decided to head to Camden where it was only 12kts, to take a little pressure off the early stages of the endo. There was quite a bit of radiation turbulence mixed with mechanical turbulence and thermals, but these days I tend to be quite comfortable in the bumps, I prefer smooth conditions but it doesn't make me as nervous as it once did.
We completed 2 circuits without any issue, then on the third takeoff roll, just as we were about to rotate, we heard a loud bang and it got windy an loud all of a sudden! I heard the instructor say my aircraft, my aircraft and take control, as we had no runway remaining to stop and the engines were fine, we took off, and continued the circuit. The climb performance was seriously degraded with the door open, the other issue was it became quite difficult to hear the radio. We reported to the tower we would be returning for a normal landing and that we had a door pop open.
I wasn't too fussed by this as I have had the door of 152's pop open, along with my seatbelt whilst in a left turn! Which is quite a bit more scary! The POH recommends either having someone hold the door shut and return to land or just leave it and return to land. The airflow from the prop and direction of travel is enough to hold the door mostly closed.
The student was reaching behind the instructor to try and close the door, this was a little more concerning as t this could have distracted or bumped the pilot whilst low and slow with an abnormal situation, not ideal!
Luckily this was quickly rectified and we landed, closed the door and decided it was time to go home.

After this I got started on my enroute GPS endo. This is consisted of sittin in the aircraft going through the basic functions of the Garmin 430 unit. Scrolling through the pages, finding airport information, nearest waypoints and flight planning. We had a quick look through the autopilot and approaches too.
The rest of the endo is reading through the manual and completing a small open book test. Much like a CASA aircraft questionaire, it is most useful to know that people have at least looked at the information once!

Next weekend I have a training exercise/short flyaway so I should hopefully have some good thing to report, as well as riding in the 206H.

Thanks for reading!