I have an ex utility company TD5 defender 110, the VIN number shows that it is an extra heavy duty spec, i can see that it has a beefed up chassis but is there any way I can find out what other parts are non standard, especially suspension, axle parts etc as i am thinking of overhauling them...

I went to change oil today and found out that the sump plug is absolutely solid, i decided to stop and consult rather than keep on going until something failed, has anyone got any tips to increase my chances of getting it loose without damaging the sump threads etc, The plug itself is still in...