Im already sailing close to the planning regulations with the current mounting being over 3m high. If challenged by the planners, my cunning plan is to point out that because it (and the angled crossbraces) are mounted on 24" fencepost spikes, it does not constitute a "permanent" installation, but installing guy wires might be going a bit too far for that argument to hold water. So just about the only option is for me to get medieval with the fencepost base, beef up the crossbracing with longer wood so that at 45 degrees it will go to the top of the lower 2.4m fencepost, take the upper fencepost off, and replace it with the steel tube.
Of course doing it that way gives me more flexibility on how high I make the whole thing. If I drill the 4m length of scaffolding halfway along at its 2m point and put a coach bolt through the fencepost at 2m up, that would mean that the whole lot would be only 4m high and could easily be swivelled down for easier access to the head. Or if I drill at 1m along, the thing would be 5m high but Id have more trouble swivelling the head down, and also have more force on the structure as a whole. Hmm, interesting times. I begin to see why towers can cost more than the gennies.
Thanks for the warning about the bicycle bits too. I reckon I might see if I can find a way to mount a spare Vauxhall Cavalier rear hub as the yaw bearing instead, Id think that should be strong enough.
Meanwhile, in anticipation of the storm, have tied down the prop.
By the way, now that my preferred blade set from Gordon has become unavailable, and Navitron seems to have withdrawn their 1KW bladeset (hopefully for re-engineering and re-issue), do you have any suggestions for an alternative? I did briefly look at the 5ft glassfibre set on eBay but my 1KW stepper motor does need quite a bit of grunt to get going and Im not sure that 5ft is big enough.
Have just emailed CMS Magnetics with a query on how much their 9ft glassfibre composite bladeset without hub would cost to ship to UK. 111 US dollars for the blades themselves works out to GBP 56, now waiting to see how much for the shipping.