After finally figuring out that it was the distance between the bracing arms and the lower chassis that was the cause of my inability to make the panel fit correctly, I then focussed on the underside. I trimmed a few mm from the panel where it was touching the diagonal chassis members but that was it. I carefully marked the chassis position on the outside of the panel - double checked - triple checked and the drilled some pilot holes. When I was sure I had the correct position I very gingerly drilled the remaining holes in the panel and through the chassis powder coat only. As the fuel tank is so close, I removed the panel again to complete the drilling of the chassis and de-burr the panel.
I followed a very similar procedure with the drilling of the rivet holes for the sides. With clecos in the already drilled base and the panel clamped in position, I marked and drilled the pilot holes, removing the panel again to complete the process. You will also notice from the photo the outline of the rear wheel arch which I very crudely applied so I didn't put any rivet holes in visible places where it wasn't necessary.
With the back panel now clecoed in place I then positioned the boot in-fill panels, marked and drilled these too for their fixing to the chassis only. Be careful drilling into the tubular chassis members. The drill bit can twist and shear if the drill is not pointing directly at the inner centre of the tube. That little piece of experience cost me two cobalt drill bits :-(
With all of the preparation complete it was time to open another tube of "black-glue". With a bead applied to all areas of the chassis where the back panel and boot in fill panels touched, I clecoed the panels back in position and got the riveter out.
I left it to cure over night before marking and drilling the boot infill panels to the rear panel and the rear panel base to the rear panel sides. Then it was "black glue", clecos, and riveting to finish the fixing.
Back panel finally on and secured - another milestone.
Whilst concentrating on making sure I got the back panel right I missed one simple but important step. BEFORE FINAL FIXING OF THE REAR PANEL MAKE SURE YOU ROUTE THE WIRING LOOM FOR THE REAR LIGHTS THROUGH THE HOLES IN THE REAR PANEL. As I found out, if you try and do this afterwards - you can't. There is insufficient space between the rear panel and the tank. I had to remove the spade terminals from the wiring loom to get the wires through. I then needed to attach some more spade terminals. Not a big issue, but easily avoidable.
I had already cut down the rear lights so that they will sit at 90 degrees to the road, so with the re-assembled loom in place I attached the rear lights and the petrol filler cap. She's starting to look something like a car now - at least from the back.
The next job on my list will be the engine preparation and fitting so I can finally get the side panels on. When I picked up the kit and got it home, I put the engine at the top of my garage - out of the way. Having now build the car in front of it, I can't get the hoist anywhere close to move it. So, it was time to put the wheels on and lower her carefully to the floor and out on to some tarmac for the very first time.