Last week estate agent David Gill fetched just over £1.3 million under the hammer for a handsome Victorian redbrick house on Northumberland Road in Ballsbridge, Dublin 4. Then he started doing some sums. The three-storey house, number 78, last came on the market in 1907 when it sold for £1,050. No doubt it was considered a hefty price at the time but since then it has gone up in value 1,250 times, rising at an average 8 per cent per annum over 92 years. All in all, a nice little earner.