In reply to MikeMarcus:
I take groups climbing there, but from 13/14 years. I expect she would find something to go at especially if you climb using all the holds.
Personally I would recommend Boulder UK as mentioned above(Preston), which is 20 mins from Bolton and avoids graffic of The Depot.
The Depot (near Trafford Centre) is a great option too. It has auto belays with plenty in the 3-5 range. My daughters ages 5 and 9 love it there. Plus it has loads of green spot problems throughout the centre which finish below full height and my daughters can do most. My eldest who is not great with heights also likes to try the whites (lowest grade adult problems, and has got up a few, but tends to stop one move below the top as they go to full height.)