Next, I checked the Property Registration Authority website on the house where Gill lived. Did he own it or was it held in his mother’s name? Nothing turned on it, probably, but my search confirmed Gill’s ownership. I kept the PRA window open and went into the Ordnance Survey to compare the PRA and OSI images. The sites looked identical, but it was easier to read the Ordnance Survey maps. I wanted to check the back gardens. If he didn’t go out the front, he must have gone out the back.

Sadie was right. There was no rear exit. The OSI map showed that to get access to the road, Gill would have had to cross through the next-door neighbour’s garden. Though, as the house next door to his was at the end of the terrace and had a boundary that abutted the public road, in theory, Gill could have scaled his fence, crossed through the next-door garden and climbed their side boundary to reach the road. Google Street View didn’t help much as to whether it was a wall or fence. Whichever it was, having Gill climb two obstacles to reach the road seemed too risky.

Unless Gill knew for sure that the house next door was unoccupied? I clicked back into the PRA window. Gill’s neighbour’s house was owned by a company called ProProperty Limited. Some kind of property development company? Strange. All the houses on Clontarf Crescent were listed buildings so there wouldn’t be much scope for redevelopment. Unless it was an executive lettings agency? I ran a Companies Registration Office search but the CRO link was down. Yet something about the name seemed familiar. I’d come back to it.

I decided to accept for now that Gill had got out somehow on to the public road without being seen. If he had, he’d have needed transport to take him to Rhona’s house. So I started thinking about Gill’s cars. And that there had been no mention of Esther’s car. Maybe she used his? But her son’s success had come relatively late in her life. Ten, twelve years ago, she would have been in her mid-fifties. That was late for a woman born and brought up in dire poverty to get used to driving a Range Rover or an SLK. I brought up pictures of the cars from Google Images. I am a confident driver but I would be terrified of scratching them. No. I reckoned Esther had a runabout, something manageable, if she drove at all. If Gill had got out the back, unobserved, and if Esther had her own car, parked on the road, he could have borrowed hers. For now, I had no way of checking if Esther even had a car. But DI Lenihan could. I’d talk to him in the morning. And if Esther didn’t have a car, maybe Gill had hired or borrowed one?