Thanks for the congratulations everyone!
To answer the questions raised... it took 15 days from getting the "Medical results received" line in ECAS (1month 1week from MR). I'm from a visa-waiver country, so possibly that could have helped with whatever security checks they do.
LVO asked for the passports to be sent to the VAC (I heard that they might only need photocopies, but it doesn't say that)
They also asked for an updated "information chart" which is just your eye colour, height and passport details.
Finally they want 2 updated passport-photos for all the family - so we're of to get those taken shortly.
The document says we will be without our passports for 6 weeks.