I think he 'offered' his resignation and we accepted it which I suppose is an agreement of sorts hence no compensation. I've never heard of a manager having to pay compensation though for breaching his contract so you have a good point, although most managers are sacked anyway if they breach their contract. (Poyet)
Yes, good point - although I feel that the wording should be "by mutual consent". The only example I can think of where a manager was sued was Dowie at Palace: he was sued by Tangoman for breaching his contract - I think Tangoman won too