Sorry for delay in responding. The model No. is SVL2413M1EB. bought September 2013.
I emailed Sony Support and they sent me a link to the manual with instructions to look for the TV Tuner driver through this. I could not find it on looking in C:Windows\Drivers as this suggested. I have asked Sony for further help and await their reply although I note from the link they sent that they say they do not provide support for the drivers.
It seems ridiculous to me that they sell a computer with a TV Tuner for which drivers can not be found, even by the Microsoft technician who took over my machine in his endeavours.