There are no hard and fast rules when re-creating the country look, it is all about creating a space that is inviting, comfortable and easy to live with(the antithesis of one made so beautiful that you don't know where to sit).
Celebrate the fact that you've more space to play with, go for an expansive look and be generous with traditional sofas and comfy armchairs in the living room, and comfortable upholstered dining chairs around a large table in the dining room.
Mix Old & New
Combine existing antiques with newer pieces and don't be afraid of mixing things up, the overall effect should not be too 'coordinated'.
Traditional furniture will sit well in a country house so period details and aged or antiqued finishes are a good choice.
The emphasis should be firmly on natural materials with a rustic feel (in keeping with your location). Use solid wood furniture and fabrics in pure wool, aged leather, natural linen or cotton.
If you can, make space for a boot-room and fill it full of rattan storage: the perfect place to keep all your coasts, wellies, dog-beds, bats, rackets, clubs, gardening kit etc.
Keep colours muted and use rugs, cushions and throws to add pattern and texture.