You could grease the propshaft Les. On mine the rear UJ nipple has a cover on it and is easily accessible. There are two at the front though, UJ itself and sliding joint. These are difficult to access through the gap in the wooden floor boards but hopefully your grease gun will reach. Note that sliding joint nipple also has a rubber cover on it but not front UJ.
Not saying this will cure your issue but clicking noises when manoeuvring car on full lock forward or reverse are down to LSD clutches slipping. A friction modifier or fresh diff oil which includes the friction modifier will cure this. A small amount of play in the propshaft is normal due to the the crown wheel and pinion mesh.
