Just a quick one if you put in side facing bench seats, seat-belts can not be fitted as the are not legal (something to do with construction regs and safety I think) as I was told to take them out of my latest 109. As regards to baby seats you could do what I did and remove the middle seat in the front row and bolt the frame of the baby seat to the seat box with brackets and rubber inserts for vibration insulation, which is quite legal but more importantly very safe it also gives the child a slightly elevated position so they can see whats going on.
Hope that is of some use
Hope that is of some use