If there's a download for the workshop manual for your Ducato, have a look and see what sort of job it is. If it is too much for you to do, you still might be able to remove some of the trim, to make it quicker/cheaper.
As said above, find the hoses where they pass through the bulkhead. They usually detach on the engine side. If these are accessible remove them and join them together. A bit of copper pipe and two clips is usually all you need. This keeps the engine fed with coolant as it by-passes the leak. Make sure the hoses are clipped away form anything moving. You just won't have a heater until the leak inside is fixed.
As said above, find the hoses where they pass through the bulkhead. They usually detach on the engine side. If these are accessible remove them and join them together. A bit of copper pipe and two clips is usually all you need. This keeps the engine fed with coolant as it by-passes the leak. Make sure the hoses are clipped away form anything moving. You just won't have a heater until the leak inside is fixed.