Hi, Ann Harper is also my ancestor and I had trouble locating her trial too. I don't have the exact trial but in "From Chains to Freedom" by Thais Mason Vol II on page 28 it talks about the trial.
On 24th Sep 1787 in the morning in Bristol, Ann Harper (17) along with Margaret Williams (13), Alice Fideo and Elizabeth Seney (18) were alll on Bristol Bridge selling grapes. Margaret told the girls she knew where they could get a silver teapot and they went togerther over the Drawbridge to Denmark Street and stopped at number 11 which was owned by Nancy Clutson. Margaret unlatched the door and went inside where she stayed for some time.
When she came back out the four girls ran away to Medcliff Church Yard. Margaret showed the other girls 9 silver teaspoons, 2 silver tablespoons and a silver cream jug. They all agreed to go to someone Norris' house on Redcliff Hill to sell the things. Alice said that Elizabeth and Margaret went into the house and when they came out they told her they'd sold 2 of the spoons and spent the money on victuals. Then Margaret gave them each 2 spoons and supposedly they all gave these to Elizabeth's brother to sell but never heard from him again.
They were found out and a few people such as maids, neighbours and a friend of Norris testified and a maid from Nancy Clutson's house also said that an amount of eight shillings were also stolen. Despite Ann not actually doing the stealing she was punished because she was aware of it and received the goods. Alice also gave evidence and went to jail. The other three including Ann were transported for seven years.
