You don’t need to remove the belt to remove the cylinder head. You can slide it on and off as you suggest. Next time you might consider replacing the valve yourself. It’s not a difficult procedure and the valves are pretty reasonably priced.
Just make sure you get everything back in time and set the belt tension when you reassemble. There is a removable plug in the lower timing cover that gives you access to a 14mm bolt for the timing belt tensioner. Loosen it to remove the belt. It makes things a lot easier.
Also, to replace a valve, you need to remove the cam. I recommend you do a valve adjustment once you have the head reinstalled.