“A site-specific flood risk assessment is required for all development (including minor development and changes of use) proposed: in flood zones 2, 3 or 3b; within flood zone 1 with a site area of 1 hectare or more; in areas with critical drainage problems; within flood zone 1 where the LPA’s strategic flood risk assessment (SFRA) shows it will be at increased risk of flooding during its lifetime; that increases the vulnerability classification and may be subject to sources of flooding other than rivers or sea”