lightweight easy to fit stage 1 + or 1-2-3 car seat - any suggestions

[roundabout1]

my dd2 is 20 mths & currently in dd1's old Britax 0/1 seat, one of those that does from birth rearward & then up to 4 yrs forward facing. Problem is it's really bulky, & I find it a nightmare to fit. Am looking for a lightweight one so I can store in the house to use when grandparents are staying up here or when friends take us out. Any suggestions lplease?

Britax 2 way elite. It is very light, fits using a seatbelt and tethers so will go in almost any car and its weight capacity is 25kg so should last you a long time. Plus it is rearward or forward facing and has a 5 point harness.

Only negatives are its 200 pounds and can only be bought in 1 place but you can order it from their internet shop.