Car Seats - Current Maxi-Cosi offer

We are due to have twins soon, so as you can imagine looking to minimize on costs whilst making our lives as easy as possible!  We have decided we would like a car seat that can be carried early on, preferably with Isofix base to fit into. We have noticed that there is an offer on a few places (John Lewis, Mothercare and a few others) which offers the Maxi-Cosi Pebble 0+, Family Fix base and Pearl group 1 seat for £350.

It seems a pretty good deal price and practicality wise, but for what seems is the slightly older models so makes sense why it is cheaper.  We are just trying to get our heads around how effective this will be for us, how good it is in your experience and how things stand in terms of babies needing to face backwards. My understanding is that the Pebble 0+ goes to around 15 months, but then the Pearl will require them to sit facing forwards, but not sure if this is too early?

Any help is greatly appreciated!