I will be purchasing Sno-socks (so to avoidthese types of situations) - but sorry I have no experience of TPMS and itsoperation.
Given it will be nigh-on the identicalsystem used on the Astra and Sports Tourer I would recommend doing a search forposts on the astra owners network. I recall there being posts on TPMS; however,in relation to winter tyres - I am less sure.
D.