I don't see why that wouldn't work. The sensors are probably 10k thermistors; Radio Shack sells them over here for a couple of bucks, and I read someplace that some laptop batteries also have them built in. Chances are really good that Maplin has some equivalent thermistor.
That's kind of expensive for the display, although the vacuum fluorescent displays do look nicer. New and used LCD character displays can be had for a lot less money, like around 10 bucks, and it's not too difficult to wire one up to a parallel port. Maplin's got them starting at 6 quid: http://www.maplin.co.uk/Module.aspx?...dID=&doy=11m11 This type of display has been used on all kinds of equipment, so there's plenty of cheap surplus displays around too.
Do a search for LCD and "parallel port" and you'll find out how to wire one up.