Tesco
Pound each (and BOGOF)
Box is so small, everything's snug inside and nothing rattles about
I can also recommend them too and also the ones from Wilko's, I usually buy one every time I go in, and they were only about 78p but I think they have gone up a little now. At one point both kits where in identical boxes, but now last Tesco's one I bought was in a very small square box which is better, but contents appear to be the same.
To prevent solution drying up, I always ensure the kit on my bike has a brand new tube which has never been opened, and once used it is replaced by another new one, and then it is kept at home for repairing punctures in front of the fire so it does not matter if it has dried up. One of the biggest problems is, when you use a tube of it, do not allow any air to get into the tube and always squeeze from the bottom, and when replacing the cap, always give it a squeeze whilst held upright to just get the solution coming out of the top, then screw the cap on.
What I find frustrating though is finding somewhere that sells only small tubes as you get in the kits, try buying one loose along with patches and they are always large and too big to fit into the kits.