Possible Clues:

• Frail, after time dressing for the outdoor life?
• Like Jane Marple's wardrobe
• Of a robust traditional or rural character, informally
• Like heavy material getting thin after short time
• Tense and feeble, like the rural upper classes?
• Of a robust conservative or rural character
• Like traditional countryman seen as robust, ultimately getting scrawny
• Of the 'green wellie' brigade?
• Countrified; like cloth