thanks for your reply. I can confirm some further info re George and Mary which was on Colin's Birth certificate, and that is that he was 39 when Colin was born in 1904, which makes his birth date around 1865, and Mary was 23 which would make her birth year 1881. We also know that George died while Colin was on his honeymoon in 1934, and I had found a George Thompson's death for May of that year which fits time wise.
Colin had a sister, Irene Mary, and a brother Alexander.
They are both dead, but we are trying to find out more through Irene's family, as Mary had lived with Irene for some time before she died.