If it was a 3 year deal and he's been here for 3 years then yes the fee will have been written off. I assumed the deal still had time to run but I might be wrong.
Is there provision for deeming a football player an impaired asset? I've never heard of it happening. A knackered tractor on a farm, yes, but a footballer who's turned out to be ****, I'm not sure about.
I take your last point but if we are offered similar money in the summer as we could have got in January, and after another chunk has been amortised, it obviously makes sense.
Either way he's a donkey and signing him was appalling business.