Blue tit or great tit visiting our nest box in early January

Hi, just after New Year we noticed what we thought might be a blue tit or a great tit visiting our tit nesting box in the garden. It was going in and out at around 10 o’clock in the morning. I know that these birds sometimes use nesting box over winter as roosting sites but it seems strange to me that it will be entering leaving at 10 o’clock in the morning when first night was Hours before then. There was no nesting material and I know it’s far too early for tits to be Nesting anyway so the only exclamation I can come to myself is that it was potentially one of those two species checking the spot out for spring as a potential site for testing?

Can someone explain what this heavy might mean Many thanks,