While waiting for a descriptive reply on how to do it.
1. can't insert drawing/pictures on this forum
2. If you are in UK check if your local library hold a workshop manual for your vehicle. Some used to have manuals or they would order them for memebers but that may have stopped now. Of course you will have to become a library member if they will get one in for you.
The last time I put a timing belt on a vehicle [Astra Estate] the belt tensioner had to be slackened so had to purchase a tool for it. It's likely that's why you can't fit yours.
Bob
May 2009