Help! Travel system recommendations - absolute max £1k

Hello! Little overwhelmed with the choice out there! Please could you give some recommendations?
We will test out in stores but always like to ask what really works for people.
We’d like something that folds down nice and compact (and easily) and isn’t too heavy.
A trusted brand that’s been well tested for safety.
Absolute max £1k (if from John Lewis can push this to £1.2k as we can use a staff discount but again, preferably less than that)
Good for mixed terrain.
Don’t want to buy second hand
Thank you!