Hi Brendan,
The first thing I wanted to do was to get the neck flat, or with a very small amount of bow before I did anything with the frets, so I fully understand your comments.
I did order a notched straight edge from Australian Luthiers Supplies for around $60, but it didn't fit over the frets on this kit or my other two guitars. Lesson learnt I suppose.
As a consequence I read on a US forum that it is possible to use a steel rule (provided it is checked for flatness first). I bought a 600mm one, laid it against the neck, marked out the corresponding fret positions on the rule with a black marker and cut out the notches with a rotary cutter. The result is shown below
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It may look a little rough around the edges, but it worked.
As it turned out I laid the neck on a bench and with gentle pressure in the centre of the neck to take the tension off the truss nut I gradually wound the rod anti-clockwise in small increments over the course of last Saturday and I got a result, a flat neck.
I masked off the fingerboard and set about dressing the frets. Only two low ones which I matched with a flat diamond file, recrowned, polished and all done.
All in all, a good first time experience.