I guess with yours it will depend on the sub frame / chassis at the rear - if that's bent then (officially) repair will probably go beyond the value. I know its a torture but you could accept the cash, buy it back and make the repairs under your own steam. At least you would know who has driven it.
I think it would be a big job to repair it, the rear "wings" have partially folded under, you can see the high spot in the photo, its the same on the other side.
I also have nowhere to put it if I did buy it back and I'm time poor at the moment, my brother suggested I buy it back and break it.
I have been collecting a few parts over the years, I have 2 new headlights, new air con compressor, various sets of suspension bolts for front and rear, spare set of refurbished bonnet latches, etc, etc. I had planned on keeping the car for some time. Last year it had new clutch, cam belts, water pump, thermostat housing, new plennun and set of coil packs, in addition to the usual service type stuff which included new MGR brake discs all round and MGR pads. Also had to replace the centre brake light and battery.
To add insult to injury . . . I had 2 Vredestein Quatrac 5 205/45 R17 88Y XL (AS) fitted on Saturday afternoon, I'd ordered them last week online - £195, they literally have half a mile on them.
I have found a 180 in silver with 62k miles not too far from me, I will probably go have a look on Saturday, at least I know what to look out for.