Is this the Tddi diesel engine?
I just did the timing belt on my Transit connect at the weekend, it has the Tddi engine, and there are 2 ways to lock the crank.
First is via a small hole thats was covered by my alternator drive coupling. You remove a small bolt and screw in the appropriate crank locking pin.
Second is to remove the starter motor and lock the fly wheel with an appropriate tool.
All of the above is after you have also locked the camshaft.
Hope this is of some help.