chances are it's not mate the other may be for an electric hood i think i was told even thought it would not have one on coupe or hatchback,vauxhall used the same wire loom for all the astras i beleave.
do you have any pics of the 3 blocks ?
the t/c one is blue.
even if you do have it you may only be part wired
have a look at the guide on here may be of some help 😃
https://z22se.co.uk/guides/traction_ ... _guide.pdf