This advice is a bit late.

If anyone rings our house and I don't recognise the voice. I ask/insist on knowing who is calling from what firm, before I tell them if me or Steve is in. If the company is unwanted like double glazing sales man. I ask them how they got our number (as it is ex-directory) and I want to speak to their manager.

It's your phone, you don't have to answer their questions. I am always polite but firm. It is understandable that our phone has been crossed off loads of sale lists and we are hardly getting any sales calls now. Hurrah