Excellent! Many thanks for all the comments and suggestions. My intention in getting a UPS is to enable an orderly shutdown not to keep the system operational during an outage. The computer is off overnight and the missed data downloaded from the weather console each morning. The weather station software does a daily back up to a different disk at 1155 every day but incredibly wipes out the previous day's backup in doing so. After the power outage unfortunately I hadn't noticed the data corruption in the 10 minutes between when power came back on for the third time and 1155 came around.......
So, a separate scheduled backup strategy is now in force with Acronis and I'll look at an APC UPS.