White correctly assessed that the 'threat' is illusory and played 26. Raf1, bringing the last piece into play but rejecting the stronger Ne6.
The game continued 26. ... gxf5? Black obviously believed White and assumed that the knight couldn't be taken; however, 26... Qxh6 was playable, when 27. Nf7 Qh5, 28. Nxd6 provided Black finds 28... g5! - a difficult move to see in advance and one that both players missed.
The game continued 27. Bxf5, persistently leaving the knight en prise. But taking with the knight would have been stronger.
27... Bxf5. Better was ... Nh5 but White will win an exchange with either knight to f7.
28. Rxf5 Qe7. It doesn't really matter what Black plays now as White has a winning advantage. 28... Qxh6, 29. Nf7 or 28... Qg6, 29. Ne6 were alternative ways to lose.
29. Ngf7 Ng8, giving up more than the exchange if White wanted to take it.
30. Nxh8 Nxh6, and now 31. Rxf8 was the most precise and would probably have forced resignation. However, Ian played 31. Bxh6 Rxh8, 32. Bf8 which was sufficient to obtain the same result. 1-0.