‘Really?’ she smiled, leaning in closer, but then quickly sitting back on realising she sounded overly effusive.

‘You sure do. Because this is the image that made me want to tag on some extra days to my trip and come to London right away!’

‘Oh?’

‘Sure did. You see, this could be an original by a recently discovered artist. Is there a mention of the paintings – or indeed an artist – in Connie’s diaries by any chance?’ he asked, looking up from the phone.

‘No. Not that I’ve come across so far. But I did wonder if Connie was actually the artist, as she’s certainly very creative in her prose … maybe she had a flair for painting too.’

‘Hmm, interesting theory. But I don’t think so. You see, I’ve seen the marking on the bottom right-hand corner of these paintings before. The first time was on a collection of three American landscapes which were recently acquired by the Guggenheim Museum in New York. Then a miniature watercolour dated 1943 was discovered here in England, in the attic of a house in Woolwich,’ he said.

‘That’s such a coincidence, as I actually live in Woolwich.’

‘Really? Well, I never,’ Ellis said, lifting his arms and turning his palms upward in a gesture of incredulity. ‘Perhaps you know the street where the house was. I have the details right here.’ And he quickly searched his phone, explaining that he’d made a note of all the information they held about the miniature watercolour on the auction house computer systems, just in case it proved useful while he was here. ‘Repository Road.’

‘Oh, that’s where the army barracks is. Maybe the artist was a soldier if the painting is dated 1943.’

‘Could be. A bundle of pencil drawings were also found there too … all with the same marking on, so we will need to work out how they’re all connected.’ Grace liked how he said ‘we’, as if they were already a team bound together in their quest to unravel the mystery of the forgotten items in unit 28. ‘Little is known about the artist, other than that they were reclusive and most prolific in the 1950s and 60s, as there are more pieces with the same marking on in private collections around the world, each one commanding significant sums at auction. But some of those paintings surfaced in America and then some later works were found in Italy. George Clooney is a big fan, which of course has helped drive collectability of the paintings.’

‘Wow! So you think the paintings in our storage unit are by the same artist?’

‘Well, I need to take a close look, but I’m hopeful,’ Ellis grinned, lifting his eyebrows.

‘And a recluse, you say.’ Grace was intrigued. ‘Does that mean nobody knows who the artist is? Rather like a Banksy of olden days?’