I managed to get this working by creating a new rooms application pool.
Then in default websites > rooms > basic settings I changed the application pool to the newly created rooms.
I still don't know why this worked but it has. Hope it helps someone else.
Plesk and cPanel are for managing shared hosting. You would install one of them if you had several people hosting websites on the same machine or VPS. I would not recommend installing them if only one person or company is going to put websites on that machine. Far from making your life easier, they will increase the amount of configuration that you need ...