French Doors

[Wagstaf]

I have a conservatory on the rear of the property put on after the property was built. The internal doors are sliding patio doors which lead to the dining room. I am looking to replace these patio doors - do I need hardwood or softwood, external or internal. The conservatory is heated by a radiator but is still cold during the winter months. Also, where can I get fench doors from for this project - they are 6'0 x 6'6. Thanks