Just to update this - I emailed ITV and they told me to email North One. So, I emailed North One and they got in touch with the organisers.

The upshot is that the total lap time and speed broadcast (and on the IOMTT website) is correct but two of the splits are wrong. The correct split for Glen Helen to Ballaugh Bridge is 3m02.145s and the correct split from Cronk-ny-Mona to the finish is 0m56.801s.

North One tell me that the official website will be updated soon.