Hi Andrew. It should have unlocked at the end of the cycle but you have a failed catch.
Thee is a tiny tab inside the lock that would release it, btu that will be difficult for you to locate at best. And that wouldn't solve the problem really anyway.
Its easy to replace and I will help you. It was already scraping as it was.
The best place to get a new door catch is: http://www.espares.co.uk
Since there are so many different ones out there, I highly recommend calling to place this order. All you need is the full model # of your dishwasher for this order. They will ship you the correct one the first time lol ;-)
Please call espares: 0844 9777 888.
In any case, I will stick with you until this is complete please rate my service kindly.
Also it is the only way I am credited for my time and expertise with you.
Once you rate, I will be notified and will add your question to my priority list so you can reach me anytime until this problem is solved.
Then you can reach me by simply replying to this message anytime.
Thank you and have a Wonderful day Andrew!
No additional cost to rate kind;-)