I have just had a 100w 24v solar panel and charge controler delivered , My question is do i need a blocking diode between the solar charge controler and my deep cycle lead acid battery, i assume i dont but thought it best to ask .Thanks.
A blocking diode between the controller and battery will not allow controller to see battery voltage. That may not allow it to ever turn on. If it did, it could not monitor the voltage correctly. Blocking diodes are sometimes placed between panel and controller. Only in special cases are these necessary.
A fuse would be a good idea however. The controller documentation should give you all the information that you need.
A charge controller is likely to be designed to be connected to a battery, and also during times when the solar panel does not produce energy. But the simplest way to be sure is to add a current meter in between the battery and the controller.