We are on the end of a 350 ish m long single phase spur just for us. There are two poles supporting the spur between us and the main line. The 350 m horizontal distance isn't a problem, however there is a 70 m (230') height difference. That first supporting pole may only be
100 m away but it's 20+ m (70 odd foot) lower, going down is OK coming back up that 1:5 is. B-)Grazing only up here. ENW came around last year IIRC and replaced the two stays from pole top to ground anchor, fitted new cutout much higher up the pole and replaced the cables to/from it, fitted new "crown of thorns". Transformer and two wire open line feed to building where it changes to concentric all unrouched.
It's that open line feed and rusty transformer that normally produce comment from the engineers. The transformer particulary so when they look at the meter board and find a 100A cutout, 2 ordinary and one E7 supply all off that feed and AIUI 16 kVA transformer...