Less the £6k extra the corsa E would have cost to buy over a regular one but yes, it’s way cheaper in terms of total cost of ownership if you hold onto it.
I wouldn’t be overly concerned on the battery degradation front. The original leaf didn’t have the best chemistry, the best BMS, any thermal management and it was a tiny pack meaning you it cycle twice as often for the same number of miles compare to the corsa.
The Tesla Model S from the same era fared much better and nearly all of them have 85%+ of their original capacity remaining and there are bucketloads of 200k+ examples out there now.