just get them to wirte a letter addressed to the british embassy, stating that will sponsor your acommondation for you and your wife, and you and your wife are welcome to stay at their property until xxxx or for as long as you like, rent free ?, evidence they own their own home ?? or rent ? and it has x bedrooms and will not be overcrowded with you both lving there. some pics of the house and of the rooms etc would help
