Failand is 'washed over' by the Green Belt and has no settlement boundary (unlike Long Ashton). Only replacement dwellings are permitted under the current Local Plan.
Check "Green Belt" and "Settlement Boundary" in the left panel.
This Green Belt interactive map shows changes to the Green Belt nationally over 5 years in red. New holes (as would be required for Failand) are rare. The changes are predominantly relatively small expansions of existing urban holes. This suggests that the only modification that would be allowed in North Somerset is outward from Bristol into Ashton Vale and relatively small expansion of Portishead, Long Ashton, Pill and Bristol Airport. Changes next to urban areas on the perimeter like Nailsea and Backwell would be hard to justify as they could expand on the outward side.