Hi Zooma,
Sorry to hear that the mounts do not fit your Mk2 Airsporter.
The three sets I have are all labeled as TO48. There is no C indicated on the packaging or the mounts.
I got them from Michael Tawn through .
I am really sorry if I have in any way mislead you. I had a Mk2 Airsporter which had the old plastic BSA scope from the Mk1 & Mk2 Meteors and as Sportsmatch TO48 mounts fit my Mk1 Meteors I was convinced that they would fit your Mk2 Airsporter.
Please accept my apologies for any inconvenience or expense I have caused you.
Regards.
Musicman