Wobbly steering, worn tyre and bumps!

Hello, and Happy New Year! Having an issue with my '99 Octavia 1.9 TDi. At slow speed (10-30 mph) the steering wheel wobbles, peaking at about 20 mph. If I let go it moves an inch either side and the car will pull very slightly right. Other symptoms are the offside (which is left for me, in Spain) tyre is heavily worn on the inside edge, the car makes some clunking noises when driving over potholes, and when I did look under the car by the wheel (to check the extent of tyre wear, I noticed one of the bushes (on the end of the steering rack?) was split and needs replacing. Finally, when reversing on full left lock (which I do daily to get out of my parking space) it feels like I am driving over a stone or something, I estimate once each wheel revolution, which I am not, the parking is completely smooth!

The car has done 230,000 km (140,000 miles).

Can I make this better by replacing bushes? Can I do this myself (have jack, axle stands, reasonable tools and some experience)? Is there anything else it could be?

Thanks