Sometimes write-offs are worth fixing if the damage is straightforward - you could choose to put the car back on the road yourself if your wife likes the car and wants to keep it.
This may make sense if:
* A decent repair shop that will fix the car to a good, safe standard and not charge the earth can be found
* You intend to keep the car for a while (perhaps even for the rest of its life on-the-road)
The car is worth nothing in the state it's in now - and if you did get it fixed and later went to sell it, you would have to tell the buyer what had happened and it would clearly be worth less, so its really only worth doing if you want to run it yourselves.
I don't believe any dealerships are offering a genuine 'scrappage deal' these days. Cars taken in on the state incentive scrappage deal 10-years ago really were crushed, but that incentive ended after a short time.
Dealers may describe their generous trade-in offers as 'scrappage deals' but I don't think they're really scrapping the cars that they take in. You might find dealers reluctant to talk to you if you offer them a totalled vehicle as your trade in.
I recall my dad taking his ancient Escort to a dealer where a minimum value trade-in deal was being offered and they told him they wouldn't give him the minimum value for the Escort because they could do nothing with it!