In Canada the rise was around 6% yesterday (news must have leaked out I guess), so the higher start here today was catching up with that since London was flatish yesterday.
Canada dropped from 7.8 to 7.35 after 16:30 today so that's a 5.8% pullback after the London close so I would hazzard a guess that the open here tomorrow will be around 345 * .942 = 320/330 although we do sometimes but not always get a slight overadjustment in the UK which may be exhibited by a wider than usual opening spread.