I'll tell you what I did. Looked at the parts manual and wrote down which spanner sizes were included in the original toolkit.
Went to the hardware shop and bought spanners of the same size, medium quality. Cheap enough for me, and much better than the originals in case of a breakdown. I also bought a screwdriver with a set of bits, and pliers. Actually I ended up doing the same with old my bikes, having put the original toolkit on storage.
For the wheel axle nut I bought a box-end spanner and cut it so it would fit in the toolbox. I don't need the open-end, and I have more leverage than with the original spanner+leverage bar. I also carry some fuses, and a set of cables and cable-ends in case I need to replace a clutch or throttle cable.