Possible Clues:

• Tract of land with particular character
• Ground close to swamp passed over by turtle
• Retinue protecting Queen and country
• Country school getting royal visit
• You find 'er in a sort of country railway
• 12 across is the last sort of thing you'd expect to fall on this ground
• Tract of land with prevailing characteristic
• It can be rugged
• Stretch of land, emphasising natural features
• Stretch of land with respect to its character