There's the boat in the lock waiting to come out. The landing stage is at an angle outside the left of the lock. The probem is that you can't begin to turn the boat until the back of it is past the extended lock walls, because the back needs to swing out to get the front in to the landing stage. So by the time you can turn the boat you are already half way past the stage. So what you have to do is,
1. Exit the lock pointing the boat away from the landing stage
2. When you are in the clear, do a 90 degree (or more) left turn to get the front into the bank. (you are now at right angles to the landing stage with the front of the boat touching the bank.
3. do a full 90 degree turn on opposte lock to swing the back in
4. Reverse back to get the boat back alongside the stage
All while the current is pushing towards the weir which is often on the right. All very good steering practive and I have to say that both Kath and I got quite good at it!
Or you can go on the Ashby canal which has no locks!