Like any siblings, there are times when isaac and Toby are at each other’s throats have their disagreements. But for the most part, our 5½ and 3½-year old boys get on really well together. They watch TV, play cars and make up games together, and generally do a fantastic job of occupying themselves, much to the relief of their permanently knackered parents.

It’s not something either Heather (an only child) or I ever experienced ourselves. I’m six years older than my brother and we’re very different in personality. We had different sets of friends and different interests, and it wasn’t until his early 20s that we really had enough of a common set of experiences to bond properly. Looking back. I think we’d both admit we missed out on something quite big as a result.

I’m delighted our boys are enjoying the positive side of being siblings much more. That’s never more apparent than when we go out as a family.

Today we went to the National Motor Museum at Beaulieu. Isaac, as is his nature, took the lead with his brother: reading signs, showing and explaining things and generally bossing him about. Toby’s not afraid to push back and voice his own opinion, but for the most part he was content to follow in his brother’s footsteps.

Where the brotherly relationship really came to the fore – much to our relief – was at lunchtime. There’s a picnic area adjacent to a well-stocked playground – as is common at most family-friendly places these days – and the boys immediately took themselves off to play together, leaving Heather and I to tag-team Kara and enjoy our lunch in relative peace.

It’s fun to watch the boys playing together. Not just because it gives us a spot of respite in an otherwise chaotic day, but because it shows me a side of childhood that I never experienced myself. I don’t feel like I missed out – you can’t regret the absence of something you never knew was missing in the first place – but there is something pleasingly vicarious about watching my own kids enjoy each other’s company.

It validates our decision not to stop at one child and – better still – the more Kara grows up, the more the boys include her in what they do too. It’s lovely to see. In some ways I feel like I’m growing up with them and enjoying a second childhood of my own.