How do I get the top open and remove the tub?
There are 2 spring clips between the main top and the front panel. Push these clips and you can lift the main top.
To replace the tub boot is the tub boot the only part I need or is there a kit which may include other gaskets? Also how do I open the top to get the inner tub out?
There is not a kit and the boot would be the only thing required to replace. To remove the top to access the tub you will need to push 2 spring clips between the main top and the cabinet front which will allow the top to lift up.