This sounds like a universal drive joint,which I have read will 'tick' at the beginning,if it is juddering it is well past that point,it will need to be replaced,you need either the LH or
RH drive shaft.You can buy this as a complete unite.You may be able to see it from underneath,when you say it judders it should show some grease or damage to the rubber boot
in the centre of the front drive wheels.You can get a new one,for about the same price of a secondhand one on Ebay.A new Honda one is about 3 or 4 times the price.This needs
to be done or you will end up stranded.