Is this a PP installed smart meter or a smart meter carried over from your old supplier?
If its an old one then the in home display may not be tottally accurate and will proberly stop workjng at some point,
If its a PP one then its proberly a minor increase which shows as 1p ph caused by rounding up. So 2.49p ph shows as 2p and 2.51p ph shows as 3p. A tv on standby or a fridge working a little harder in warm weather can cause it.