One of the failures on my MOT says, drag link end ball joint has excessive play nearside. Does this mean I have to replace the whole ball joint?

that will probably refer to the track rod end mate

5 minute job to replace those

Trying to locate parts and getting very confused, is there a difference between a tie rod end and track rod end, sorry if a stupid question amateur mechanic and all that.

no mate they are the same thing @Adtree