1. Is there a Manufacture Warranty if so, how long?
2. You say online weight is "less than 6kg" - what is the actual weight?
3. What are the dimension of the buggy when set up.
4. Is it easy to set up and fold? Can it be done with one hand?
Most of this information you would get if clicking on the Full Specs part, which will open. The open stroller dimensions are not issued by the manufacturer anywhere, so I can only tell you at this time that the width should be 40 cm. The Height and length are not officially said anywhere, however, I can tell you that it will be similar to the same category buggies, so height-wise, plus-minus 100 cm, and length-wise, about 80 cm maximum.
Only the warranty is set by the manufacturer/seller. Normally, it is 12 Month Guarantee for the Bizzi Growin stroller, but be sure to ask the retailer you buy it at to be sure.
Fold-wise, it's not a one-step, one-hand movement, from my point of view. It is not a difficult fold, however, and I wouldn't really base my decision on that.
What I want to tell you, if you're thinking about it, is that from my perspective, the manufacturer doesn't provide many details, and the buggy is too simple to be sturdy. I would probably go for a more comfortable stroller for my child, to be honest. If ease of use and fold and comfort are on your mind, check the Chicco Goody Plus or the Easywalker Jackey, they fold by themselves with only one hand movement. Magical! And their seats are more comfortable for the child.
P.S. We don't sell this stroller, nor any other stroller here on Strollberry. We only provide information.