APTMAN - I think that ADSL2 speeds are dependent on distance from exchange rather than cabinet - I`m 2.7 km from the cabinet, and you can probably add another 2km for the distance to the exchange (although not sure where I would get the exact figure). Going on the chart on this page..
I probably wouldn`t see much benefit from ADSL2.
FTTP OD is not currently being provided commercially - think it was pulled temporarily due to high costs.
Regarding the fixed wireless option -I`m going to contact AB internet - I think they`ve done some projects in Perthshire based on point to multipoint microwave technology. There may be some mileage in pursuing this but god knows how expensive that would be, or what kind of a bureaucratic nightmare it would involve!