Made during 1980 - 1985, the Navitimer 2400 quartz (Ref 81470) is called the "Cosmos". I've also seen it referred to as the "Mars" - not sure if this is an official name or not. It is a close relative of the 2100 Pluton and 2300 Jupiter models. Next to no information about it anywhere but the movement is the same for all three models - a Swiss ESA Y2 900231. I suspect differences are just down to the dials/bezels.
Here's a pic from Navitimer.net
Based on the lack of information on the 2400, it would seem to have been the least popular model and so I imagine will be somewhat rare. The movement in this range does not have the best of reputations (Breitling changed to a Japanese quartz movement for later Plutons/Jupiters) and once it goes wrong,from what I can gather, that's it - it can't be replaced/repaired. As a result, I would imagine only collectors would be in the market for this watch rather than someone looking for a cheap Breitling for daily wear. As to what it's value is, a tatty one without the bezel but in working condition sold for €290 last month. The UTC module will add to the value but I would see anything over £400 as a bonus
You may be interested to know that a gold Cosmos, claimed to be a gift from Breitling to King Hussein of Jordan, is currently on sale at chrono24 for €8,900. You'd have thought with the current price of oil he wouldn't need to flog his old watches
Let's see some pics of yours!
