What now for Sergei Skripal?

As Sergei Skripal is reunited with his daughter Yulia at an MI6 safe house in the country, the great novichok mystery is just that, a total mystery. The police have traced every bit of the nerve agent and feel certain the near-fatal dose was delivered to the Skripals on the front door knob of the former double agent's home in Salisbury. But they are nowhere near finding the culprit or culprits who smeared the nerve agent onto the door and most of what has been made public is based on inteligent conjecture. The Russians had made novichok, Skripal had worked for MI6 against Moscow, ergo, Russia is to blame. It's pretty good circumstantial evidence but it IS circumstantial. Putin has now come out to say it couldn't have possibly been novichok that made Sergei and Yulia ill because if they had been poisoned with novichok, they would have died instantly. Well, he should know, with his KGB background. But the fact that neither Skripal died is perhaps an indication that this particular strain of the nerve agent was not so deadly after all, or the doctors and nurses were so brilliant that they managed to outsmart the novichok. Either way, Putin has expressed relief that his former GRU spy has survived and is being well looked after by his MI6 minders. Time for a big belly laugh!! But what now? What will happen to Sergei Skripal and his daughter? They can't be protected in a country house for ever. And will the police ever be able to pinpoint who was to blame? It seems highly unlikely. If it was Moscow behind the murder plot, even though the novichok failed to kill, it was still such a well-planned operation that no one seems to have a clue how it was carried out, whether it involved one or more individuals, what their nationality was and how they managed to escape being spotted. And where are they now? Perhaps in 20 years time when a police "cold case" team in Wiltshire goes over all the evidence and the CCTV footage again, they might spot something that is being missed by the current investigators. I hold out little hope.