Advent are only sold through Currys / PC World (who are the same company anyway).
It is always risky buying any product that is sold through only one outlet as you have no idea what the quality is like as it does not compete on the "open market".
Many of these types of laptops are made in "generic" factores in the far east and just "badged" by the outlet who buy them. You may find the same laptop sold in say Germany with a totally different name badge on it.
I think you are far better buying a "branded" laptop from a compnay who sell in many shops and in many countries.
"Name" brands like Samsung, Toshiba, Lenovo, Sony, HP, Asus, Dell etc do have to keep their quality up or they will soon get a reputation of being a poor quality brand.
I am not saying buying an Advent would be a mistake, but as it is only sold through on type of shop you have no idea how good the laptop really is or what the quality is like.