Check with your motor factors - you can often get new track rods at about 15-20 a time... Hence i said earlier with a Mini its cheaper to change the rack and it will be 'as new'think I'll just have to buy a new rack then, it seems a bit silly that you can't replace just the track rod though!
Always lap in ball joints... and if the bottom one has play in it then deffo dont re-shim - replace...