He shakes his head. ‘Nope – staying at Isha’s tonight.’

‘Ah, right.’ I grin at him. ‘I still can’t believe it’s been six months now. Honestly, I’m the greatest matchmaker of all time. This must be how Paddy McGuinness feels whenever there’s a Take Me Out wedding.’

‘Who said anything about weddings?’ I swear I see Harv blush as he fights back a sheepish smile. Have I tapped into something he’s genuinely thinking about?

Before I can probe any further, he starts walking. ‘OK,’ he says, ‘by the time we get to the Tube, we have to name every Premier League top scorer since 1993. Without googling.’

‘Right.’ I nod, feeling a powerfully simplistic delight at the task in hand.

As we turn the corner, though, we pass a street sign that reads Foster Road, and out of nowhere, a strange electric shiver passes through me. Like I’ve just remembered I was supposed to do something important, but I can’t recall what …

Harv is striding along with his lips pursed. ‘OK …’93 … Well, it’s got to be Alan Shearer, hasn’t it? Or maybe whatshisface … the guy that tried to be a rapper for a bit … Andy Cole! Or hang on, maybe …’ He breaks off mid-sentence. ‘Wow. Pretty weird place.’

I stand frozen to the spot beside him, my mouth hanging open as I stare up at the building in front of us: a squat red-brick house with an uneven roof and a precariously wonky chimney. It’s almost like it’s been dropped onto this street by mistake – one snaggled tooth in an otherwise perfect mouth.

‘Sort of a Harry Potter vibe,’ Harv says. ‘Who d’you think lives there?’

I’m barely listening. Heart pounding, I take my watch off and examine the back of the face. The inscription reads: 15 Foster Road, Bloomsbury, WC1A.

It never once crossed my mind to come back here. In fact, I realise now that this is the first time I’ve actually thought about 15 Foster Road, Bloomsbury, since being here in 2010.

It’s like that whole afternoon had been wiped from my memory until now.

That strange sense of unreality sweeps through me: the same feeling I used to get in the watch-seller’s presence. Like I’d slipped off the grid somehow, into a secret corner no one else could see.

‘Can I just check something?’ I murmur.

I walk across the road to the bottom of the little flight of steps that lead up to the bright purple door. The gold number 15 glints sharply in the sunlight.

‘What are you doing?’ Harv asks, arriving next to me. ‘Do you know who lives here?’

‘Not exactly, but—’