The usual way with grid-connect is to have a proper grid-connect inverter, the electricity company will not allow you to connect without a "G83" certificated inverter - for the time being that means one of the expensive "Windy Boy" inverters (around £1500 for 2.5kw) - then you'll need a special meter from the electricity company (around £80-200) according to company, THEN you use the mains as a "battery substitute" - you feed excess in (and get paid for it), and use the mains normally in times of no wind!

We desperately need more affordable G83 inverters, I know Ivan's testing some small ones from a Dutch company!
The other way would be to go the battery bank route, and use the inverter that comes with the kit - it's quite adequate for MOST household appliances,and does give you "independence" from the grid, but you'd need separate wiring, you can't just "plug it in" to your household system.
Sometimes, a good way to use any "excess" is to have a dump load controller wired to an immersion heater.
In theory, a well-sited 2.5kw turbine should produce roughly the average family's electrical needs over a year
As for planning, ring up your local planning office, and tell them what you want to do, and go with whatever suggestions they make - often they're friendly and helpful - it makes a change for them from boundary disputes!
Good luck!
