Hi Taffy,
The fuse for the inverter is to protect the inverter. You also need to fuse the wiring from the battery to the inverter. To protect the wiring from meting and causing a fire.
For a start what voltage system do you have, what size wattage of the inverter and what is the wattage of the largest appliance that you will be using.
Fellow Taffy here from Newport, Gwent but now live in Australia.