I have visited a local Hardware store that is in itself a magical emporium of 'Maker Delight'.

They can supply fastners, tools and metals in the forms of sheets or bars.
Like a book shop I am genetically predisposed to buy something in there !
I was going to buy some strips of 3 mm plate but they suggested some specific strips that are specifically made not to bend rather than plates of Aluminium.

Previously I obtained four 250 M8 threaded rods. These are to support a cover and the Solar Cell and other aspects.
Four 500 mm x 38 mm strips later I got to drilling some holes. The strips will be supported by the rods. The threaded rods allow a setting that can be adjusted.

As will be seen that PV has a hole in each corner, the manufacturer intended these to be places that could be hooked onto something. They are in fact M8 holes which take the bolts I had also bought quite nicely.

There followed an element of too and fro to get the PV into the right position but once happy I was able to make some marks for the bolt holes.

Once these holes were drilled I was able to put it all together !

The Spars are deliberately longer, the rear ones so that the LoRa antenna can be mounted, the front to provide extra height for sensors.
The bolts are also overlong so that PV can also be raised so that any extra height can be provided for the 203 mm diameter wheels.