I think I've nearly got it working, but I'm using a continous form, so the buttons appear on all the controls, is this going to cause issues?
If so I've seen that I can change the format of the button, conditional formatting but if I go into design view of the button then up to conditional formatting it is not highlights so I cannot pick it as an option!!
If you place the code snippit in the Form_Current event procedure (as well as the drop down menu AfterUpdate event as suggested by Goldy) the button.visible property will change as you navigate records.
You can reduce screen flicker by modifying the code like this:
If Not [searchali].Visible=([Status]='Washed') Then
OK you'll not get the visual feeback that you'd have if the repeated CommandButton could have criteria formatting but I don't believe it's possible with anything except TextBox controls. This is an acceptable compromise that, as I've said, is used in setting properties of CommandBar (ToolBars, MenuBars, SubMenus) controls so your users should be familiar with this idea.