Lola and Liberty see Alex’s mother as a moving party host. So I was blown away when she offered to come and help with childcare for a whole week. It was a bit of an emergency. Rosanna, the nanny, decided to take a last-minute vacation to Manchester – just as she was about to go into lockdown.

I thought to myself, “Who is going on vacation to Manchester? I can’t imagine what she’s going to do there? Visiting the Arndale Center? It’s a little strange, but at least I’m covered for the week she’s gone. I’m surprised when I open the fridge and see a surprisingly glamorous bag of deli meats from Partridges in Chelsea. She’s not one to buy bulk tea or custom-made baskets.

In fact, all she eats is pot noodles from Bombay Bad Boy — and that’s why Liberty constantly yells “noodles” at me, but I keep saying no because of the E numbers.

I am wary of this bag; it might as well be lipstick on a partner’s white shirt. What is happening here? She lives with me all week in North Kensington, then comes home to Hackney to see her mum at the weekend.

There’s a giant Tobelerone in the plastic bag and he’s yelling “she’s cheating on someone else’s kids” at me.

Is she really taking a well-deserved rest – or is she having a trial week at a new job in Sloane Square? I start to imagine tracking her down and confronting her if I spot her in SW7. I have to pull myself together; I worry for nothing. I am now concerned for his well-being. I keep texting her for breaking news on the Covid-19 crisis in Manchester in case she hasn’t seen the news – but she seems oblivious to any danger. My deepest fear is that she won’t be able to come back because she will be quarantined – or even worse, that she will pass the virus on to us.

As I left, I handed him a bottle of vitamin D spray – as a weapon against Covid.

The story continues

Nothing seems out of the ordinary, except that I realize that she left her keys on the bed. But she assured me that she would be back next week.

We pick up Alex’s mother at Paddington station. The girls rush to meet her as they spot her among the crowd. They grab her legs chanting “Grandmother, Grandmother” much to the amusement of passers-by, until she almost loses her balance.

It feels like she’s saving the day and the planet while she’s at it. One morning, I find her rummaging through my trash can, recovering the items that have been forgotten for recycling: a pot of yogurt, a small pot and a piece of cardboard.

Has it become the recycling police?

“If you can’t spare five seconds saving the planet for your kids and rinsing a jar, you can always put it in the dishwasher. Shame on you!” she growls as she brews her morning tea.

Stepmoms are known to be picky, but she’s definitely not your average. Since Alex’s death, we’ve become closer – of course, we talk about him all the time. He’s Alexander to her and Alex to the rest of us.

But as we walk the dog together, she encourages me to find a father for my children. We stop to chat with a complete stranger who also has a dog. “He looks good,” she said, as if he might agree.

“The girls have a father,” I say. “He’s just not there.”

But she’s right, really. It’s a very estrogen-rich child care system – no dad, no stepdad, and my dad isolates himself; the only man in the house is a muggle.

But even though Alex is no longer there, he is still the common denominator. She reminds me of it: the good, the bad and the ugly. She always brings a little keepsake: a picture he drew when he was four, a photo of himself, even a lock of his blond hair.

I even gave her mom the keys to my apartment to keep – not exactly practical when I lose them when she’s miles away, but it’s a gesture. I’m lucky to have her, that’s the truth. Now that she is Lola and Liberty’s grandmother, she spends all her time photographing and filming them like a Japanese tourist.

Ok she tells me I’m manic and need to relax or talk loud and maybe have ADHD. There are no teaspoons, so she brings her own. She has to hide some chocolate from me and there are no hand towels.

She will only eat from star or heart plates, and refuses to eat from plates with a flower pattern. But most of the time, we live in harmony. She sings to muggles You are my sun Where Hush little baby and gives her some healing while stroking her head and holding her paw. It’s great that she likes the dog – no one else has the patience to put up with it.

But we are a deadly combo because neither of us can make decisions. She spends a lot of time walking around the kitchen in her pink dressing gown saying, “I don’t know, it’s up to you.”

That’s when Grandma terrifies Lola’s four-year-old friend on an unplanned play date at the local park. “Harry! Lola screams at the top of her voice. He’s his best friend.

They want to play Rapunzel and Alex’s mother offers to be the queen. Instead, Harry casts her as the Wicked Witch. She immediately goes into full action mode of the method, shaping her hands into claws and speaking in a high-pitched voice threatening “I’m coming to get you!” Harry is petrified. “Whoa – that’s way too scary,” he shouts as he runs to hide behind his nanny.

After a week, Grandma is desperate to get home. It’s not because she doesn’t like children, but after being dragged to the floor for endless rounds of ring-a-ring o’ roses, crouching uncomfortably on the floor building Lego castles and doing ballet with Lola, at the age of 78, her back protests.

“OK, see you later!” I say. The children give him a big hug and we walk away from the station. I still feel a pang of sadness at that moment as another part of Alex is gone.

I’m expecting Rosanna to come back Sunday night. She has been with me for four years and has never been uncertain. He arrives at 8:30 p.m. Where is she? I try to call him and it’s constantly busy.

Will she come Monday morning? It’s Lola’s first day at school – a big moment in my calendar – surely she won’t leave me dry? Where is she?