.... but your thread needs a bump and the only comment I can make is purely subjective and influenced by past experience.
So on those grounds I would be uneasy buying from Comet (with Dixons having merged)
Any computer and particularly a Laptop may develop a fault in its early stages.
If this is soon after purchase some firms are more ready to swop for replacement.
As the weeks roll on the chances of instant replacement diminish and the out-sourced repair outfits may come into play.
I have the feeling that Comet are not the most cooperative in having any fault corrected quickly and the new gizmo may spend a long time away being fixed!
I hope I am wrong on this, but that is how I would react - if my "friend from Matlock" had asked me.