Can you tell me what the legal position would be if my son was simply to offer to sign the house over to his ex-wife and walk away from their relationship and home?

If and when the house is sold, would he be entitled to a larger proportion of the proceeds, as he contributed more to the deposit?

Your son cannot just sign over to his ex unless the mortgage lender and both owners agree, as he is bound to repayments as a joint borrower even if he leaves. If things remain as they are and he does not or cannot sign over, unless there is anything in writing to the contrary, he would get back his higher deposit from the proceeds of the sale. After deposits are accounted for, the proceeds should be split equally.

What does a divorce cost? I have been separated for eight years, we have one child aged 15 living with me. We have no property to sell and things are very amicable. I have been told a divorce can cost up to £1000 but this seems a lot.

All divorces are different, but given the lack of things to fight over, I estimate the cost to be £750-£1000. Because you still have a child under 16 you must go through a court action with all the paperwork and costs that involves, though you probably won't need to appear in person. If you wait until your child is 16, you may be able to use the Simplified Procedure forms, and pay no legal fees at all, only a court booking fee. www.scotcourts.gov.uk

My will is 12 years old and some of the people mentioned in it have moved, and one has died. Do I need to go through the expense of changing my will each time something happens?

Not if the will is drawn up properly. A will should anticipate future moves and deaths, and provide alternatives, so no part of the will goes to someone unintended - or go to the government in the absence of a beneficiary. And don't worry about addresses. As long as they were stated correctly at the time of making , and the person is identified, it does not matter if they have moved. But it is worth reviewing your will every few years anyway.

I bought a microwave from a department store, but it would not heat food properly. I thought there might be a simple fault like a loose wire, so opened it to see if I could fix it. I was unsuccessful and took it back to the shop. They told me I invalidated my warranty by interfering with it. I paid for additional warranty cover when I bought it.

You didn't need to take out the warranty, as the law gives you an automatic legal right to a refund if the item doesn't work. But by interfering with the innards, you have made it unlikely it would be accepted that the fault was in the machine beforehand. You shouldn't have touched it - you would have got a replacement or your money back by just taking it back to the shop.