That's interesting to hear. If an Anniversary is struggling it must be pretty tough!
Embarrassingly I overworked my old Anniversary last year on a 40�C day cutting 200 metres of 6ft tall roadside grass and the motor locked up. (Yes - tut tut a mechanic should know better...)
I've got the motor out but busy swapping over a gearbox in a 4x4 at the moment so haven't had the time to look at it yet to see what caused it to lock up.