Huge sympathy factor. Much stronger anti-terror legislation. The new Conservative Party becomes quasi-fascist.
Any anti-terror legislation would pass, but would probably be on an equal par, probably even less extensive than current post 2001/05 legislation (and thats not mere partisan bullsh-ting for the record
) Things would have tightened up in Northern Ireland and the events there of 1985 would not have occured or been stalled.
The Tories would have forgone an extensive leadership campaign (the suits would have made sure of it) Willie Whitelaw, then deputy would have been PM through to the 1988 campaign (they wait five full years) where another leader would see them through. They would probably win but not by a landslide and Labour would likely get in in 1992/1993.
Thatcher going over the Westland affair in 1986, now there's a juicy what if
Brittan stays, doesn't sod off to Europe a few years later, no Richmond by-election, perhaps no William Hague...